Do you think it’s appropriate for a partner to get turned on by one of their other partners and then ask a different partner for sex? Especially when they know that their partner was turned on by someone else?

This is the kind of thing that really differs between people and relationships - there is no all-encompassing statement anyone can make about whether it’s “appropriate” in general. If it works for your relationship, it works. If it doesn’t, don’t do it.

If it makes either person uncomfortable, then it’s probably not healthy or appropriate. If everyone involved is okay with it, then it’s not a problem.

Sometimes, you just can’t control these things. Say you’re in a long distance relationship with someone, and have another partner you live close to. If you’re sexting with your long distance partner, and then you’re really turned on and take that sexual energy to bed with your other partner, that seems fine to me. If you go on a date with Bawb, and he can’t take you home at the end of the night because he has an early morning meeting, but you were really gearing up toward a sexy evening, so you meet up with another partner for sex, that seems fine to me. 

Of course, if your other partner is uncomfortable with that, drop the issue. Don’t be insensitive and say things like “Matchew got me really turned on, and now I want to have sex with him, but he’s in another state so you’ll have to do.” Don’t be obvious or obnoxious about it.

Don’t use someone to get you revved up for someone else’s benefit. If Garthus puts all the effort into a romantic date, but you package that well-stroked libido up at the end and deliver it to someone else, that’s not cool.

Ultimately, this is something to work out with your partners. What are they comfortable with? How do they feel? That is way more important than whether an internet advice blogger thinks something is or isn’t okay.

I want to be in a polyamory relationship with my best friend and my current boyfriend who I love, but he is so against it he won’t even allow me to explain the different types of poly relationships there are… I really want to be with the both of them and I just don’t know how to deal with this. I haven’t engaged in anything with my best friend but I have talked to her about my issues and she even told me she wants it too, what should I do?

If your boyfriend is so against the idea of polyamory that he doesn’t even want to learn about it in the abstract, it doesn’t seem likely that he’ll come around to the idea of being in a poly relationship himself. There is no magic set of words or actions that you can take to change another person’s way of thinking or feeling.

If you really want an opportunity to date polyamorously and/or to date your best friend, it sounds like you may need to leave your current boyfriend. If you want to stay with your current boyfriend, you may need to let go of the poly dream, at least for now.

Note: Every time I give this kind of advice, I get a flood of comments, reblogs, and messages telling me not to be so fatalistic - that people can change, that I shouldn’t tell people to give up, etc. - but I think that can dangerously deny the agency of the other party and is unfair to both the letter writer and the s/o in question.

If someone messaged me saying “my girlfriend is VERY against anal sex, and doesn’t even want to talk about it or read erotica depicting it, but I think she’d enjoy it if she just tried it, and I really want to,” I don’t think it would be fair to that person’s girlfriend to dismiss her opinion as something that can be changed with enough gentle communication and information. I would not advise that letter writer to just keep bringing it up or make the false promise that they should hold out for their girlfriend to eventually come around. She doesn’t want to. She doesn’t have to. It doesn’t matter whether someone else thinks her reasons for not wanting to are flimsy, or that she’d love it if she gave it a chance.

We cannot assume or expect that every monogamous person is secretly a repressed polyamorous person who could and would be happy being polyamorous if they were just exposed enough to it, if they were communicated with in just the right ways. Even if you believe polyamory is a choice anyone can make, not everyone is obligated to make that choice, and not everyone is going to. 

I was dating a woman who began making me feel decidedly uncomfortable despite her own multiple poly relationships, and eventually I broke off the relationship because of too many ignored calls,texts, broken engagments, and a general sense of unwelcome. Later she called me a toxic narcissist among other things and I broke off contact. Do I have to let her back in my life-what my current partners are rooting for? Or can I let this bridge stay burnt?

You don’t want this person in your life, you don’t have to include this person in your life.

Why are your current partners wanting you to get involved with her again? Do they have connections to her?

Do they not understand how hurt you were, or do they know the whole story and still think you should let her back into your life?

Does she even want to get back into your life - are you ignoring pleas for reconciliation on her part, or do your partners just think you should reach out to her?

No matter what, if someone made you uncomfortable to the point that you decided to cut them out of your life, no one should be pressuring you to change that. Tell that to your current partners clearly - this is not something you are open to negotiating about or reconsidering. If they don’t respect that, think hard about whether they’re healthy for you to date.

On the flip side: I try to take all letters at face value, but since I only get one POV, I never get the whole story. If a bunch of otherwise reasonable people in your life are all pushing for you to do the same thing, and you’re the only person operating with your “I was deeply wronged by this unilaterally evil person” narrative, consider listening to them.

Maybe “you overreacted to a comment this person made, and your scorched-earth policy is doing more harm than good to the relationships in your community, and it might be worth trying to heal this a little bit - you don’t have to start dating them or be their friend, but maybe hear out their apology” is a position worth hearing. Maybe. I put this as the post-script instead of my actual advice because it’s not my go-to advice. But since all your current partners are pushing for something, it might be worth it to at least hear out their reasoning.

My partner tends to do things that are either hurtful or just plain disrespectful and then is upset when I’m unhappy with them, even though, they make comments on these things again later saying how they wouldn’t want to do those things to partner x and y because it’s ‘rude’, 'hurtful’, and/or 'disrespectful’, yet, they cannot show the same regards to me or any other partners (whom are not x or y). How should I deal with this? I feel as if they don’t have any care over how things make me feel.

How should you deal with this? By leaving this relationship. If your partner makes you feel hurt and disrespected, then turns around and gets upset with you for feeling hurt and disrespected, then insists they wouldn’t treat their other partners like that, and you have a general sense that they don’t care how you feel, LEAVE THEM. This is not a good or healthy relationship and you don’t deserve to be treated like this!

I’ve been happily in a relationship with my best friend for 3 years & always been honest about the fact I wasn’t mono but nothing happened until last weekend where I met a guy I really liked & drunkenly kissed (a lot). Now the shitty situation: my partner feels betrayed & this other guy wants a serious relationship (I don’t) & doesn’t know I’m poly. I’m new to poly, I don’t know what to do

You say you’re “new to poly,” but I’m hesitant to call this situation polyamory. It’s unclear here what the terms of your relationship with your partner really were. You say you have always been honest about not being mono, but did that extend to making sure your partner understood that you intended to pursue people outside the relationship if and when you got the chance? Or was it framed as just something about yourself rather than an explicit expectation of your relationship?

If you have been in a relationship with someone for 3 years without working this out clearly and explicitly, they may have been under a different impression about the nature of your relationship. In your eyes, you were a poly person who just happened to be only dating one person because no one else was in your life at that time. But in their eyes, was it a monogamous relationship? You cannot rely on assumptions - terms need to be clear and consented to by all parties.

Find out why your partner feels betrayed. You need to be really honest with yourself about what was explicit and what was assumed when you said you “weren’t mono.” 3 years is a long time to let someone assume your relationship is monogamous. It sounds like you needed to do more communicating with your partner before getting intimate with someone else to make sure they understood what you meant by “I’m not mono” and are okay with those relationship terms. If they consider what you did cheating, you need to engage with their feelings on those terms rather than insisting that they implicitly consented by continuing to date you after you said you weren’t mono.

As for the other guy, if he wants a serious relationship and you don’t, then tell him no. If he doesn’t know you’re poly - if you got together with him under the implication that you don’t currently have any other partners - that is a major problem, and in my opinion, a consent violation. But it sounds like your bigger focus right now needs to be on your existing relationship, not figuring out how to say “Hey, I know you think I’m single and you want to date me, but actually I have a long term committed partner and I don’t want to date you, but let’s keep making out because that was fun.”

my bf is poly and i am not and he is in love with his best friend and he is deeply ashamed. it is destroying him mentally. what would you say is the best way to talk to him and tell him that i am not upset and that i want to help him be happy again? i know he doesn’t love me any less, i just don’t want to see him on the brink of self harm because he’s so ashamed of his feelings and who he is. i don’t know how to help.

If your boyfriend’s reaction to this is deep shame and self harm, he needs to see a mental health professional asap. That is not a normal or healthy response to feelings of guilt or frustration. I wrote about this in another post here.

It’s unclear from your message whether he’s pursuing this relationship or whether he’s staying monogamous for you. If he’s pursuing the relationship, and you’re okay with it, he needs to find a way to hear you and trust you and accept that this situation is okay. If he’s not pursuing it, he needs to let this go. Having feelings for someone else but not acting on them is a pretty common experience for people in monogamous relationships. He hasn’t done anything wrong by having these feelings. 

Let him know that you’re not upset, you know this doesn’t change the terms of your relationship, and that having feelings for other people while in a relationship is a normal thing. He hasn’t committed any cardinal sins of relationships or wronged you. If he can’t hear you when you say that, if he continues to be “mentally destroyed” and “on the brink of self harm,” he needs to see a mental health professional. You are not responsible for his feelings, and it sounds like there may be a bigger issue here that you can not and should not try to fix on your own.

I don’t know your boyfriend, or you, or anything besides what you sent me here, so I want to be cautious about accusing him of something I don’t have much evidence for, but I do want to say: threatening self harm and making a spectacle about guilt and shame like this can be a manipulation tactic. Saying “I have feelings for someone else AND I’M DESTROYED MENTALLY OVER IT” can be a way to make sure you don’t have any room or rights to get upset. If you two are committed to monogamy together, and he’s nursing a crush on someone else but making it your problem, that’s not okay. If this becomes something that drags you down or silences your own ability to ask him for things, think hard about whether this is a healthy relationship. 

I’m a high schooler with a crush on a girl, but she’s already dating my sister. Is this just teenage rebellion or something? I know it’s weird and I’ve heard it’s basically incest, but I don’t feel that way. Is it really incest, and should I leave this whole thing alone?

Crushing on someone who is dating your sister is not incest. On any level. Whoever told you that is wrong.

It is certainly uncomfortable and frustrating and annoying to crush on someone who you can’t pursue, and this probably won’t be the last time you feel like this. Learning self control around inappropriate crushes is a good skill that will serve you well throughout your entire life.

The best thing to do is, yes, to leave it alone. Crushes fade, but if you destroy your relationship with your sister over this, that will be much harder to repair. It is not wrong to have these feelings, but acting on them would likely hurt a lot of people. 

Try to minimize your time spent around this person. If she’s around to hang out with your sister, find somewhere else to be. Resist the urge to flirt. It’s generally impossible to just turn off feelings entirely, but don’t indulge or cultivate them. 

Ok so there are these two men that are friends and share me in bed and i am in a “relationship” with both of them. It is clear that it is mostly sexual and they only want to sleep with me. Is it a poly relationship still?

Lucky for you, I have a whole FAQ page on whether a certain situation “counts” as polyamory!

How do you know if you’re poly or just a swinger?

How do you know whether you want to quit your job to become a full time childcare worker, or you just like babysitting your neighbors’ kids sometimes?

How do you know whether you want to move to Hawaii and become a pro surfer, or you just like taking the occasional beachside vacation?

It all comes down to: is this something that you enjoy primarily as an occasional sexual activity, or is it something you want to incorporate into all your relationships and your entire life?

Read about it, think about it, discuss it with your partner. Ultimately, there is no magical “sorting hat” that can tell you whether you’re poly or not. You know yourself best!

P.S. The word “just” there is unnecessary. No way of being in relationships or expressing your sexuality (as long as it doesn’t hurt anyone else) is better or worse than anyone else. Being a swinger isn’t a lesser version of polyamory; it’s just another way to be a sexual being! 

I just started poly and I’m the mono side of the monopoly. It started when she started falling for an old love again online and I have never had anyone but her. Idk what to do to find someone too. No one but her has ever showed interest in me.

Dating is hard for everyone, trust me! But don’t get discouraged because it’s been hard in the past. If you want to find someone to date, the best thing to do is to be persistent but respectful, and put your best foot forward but be genuine too!

If you’re just trying to get into the dating scene, anywhere and anything works! I don’t know how you met your current partner, but consider continuing to do that! Get involved in a local scene - blues dancing, rock climbing, bird watching - where you can meet people. For the most part, dating for poly folk is pretty similar to dating for mono folk. Find people to meet, meet them, flirt, fail, flirt, flirt, fling, date, etc!

It can be extra hard to meet people who are going to be okay with the poly arrangement. I’d say that about 2/3 of the men I meet outside explicitly poly contexts back out when they find out I have other partners. If that’s your concern, fear not! Many poly folk have good luck with OKCupid accounts, because they let you be clear about your nonmonogamy and filter for other people with the same stated preferences. You can also go to polyamorous meetups in your area to meet other people who are already down with polyamory. 

But there is no rush. You don’t need to find someone else to date just because your partner is dating someone else. You don’t need to prove to yourself or anyone that someone else could be interested. If you’re happy with how things are, don’t let external pressures make you feel like you have to find a new partner. 

Hi, I’m a girl and I like the one guy. He just told me that he really likes me too and I was really happy, but then he told me, he already has a girlfriend, but when the time comes, he would be really happy to be with her and also with me in polyamorous relationship. I won’t lie, I was a little bit shocked, but also very happy. But I don’t know how would that work. I mean I guess I’m poly too, and also bisexual, but I’m scared, that I won’t have feelings for her and just for him. What should i do?

It is a misconception that all poly relationships must be “triads” where all people date each other. If he wants to be with her and also with you, he may have meant that he just wants to date her and also date you. You don’t need to also be romantically or sexually involved with her. This is generally called V-shaped polyamory.

If he actually made it clear that to date him you’ll also have to date her, don’t do that. It is not healthy to be pressured into a relationship for any reason, and it is unfair to both you and her to force a relationship without giving it room, time, and patience to organically develop (or not). You may really like this guy, but that is an inappropriate requirement for dating him, and you don’t have to do it.

Also, I’m wary of the “when the time comes” comment. If he is trying to keep you on the line while he works to shift his monogamous relationship to become polyamorous, that isn’t very fair to you. It also puts you at risk for being seen as a threat or a “secondary” by his current girlfriend - if she has to give permission for him to date you, but not vice versa, it sets up a potentially unhealthy power dynamic.

In conclusion: Be careful with this guy and do not tolerate anything from him that makes you feel disrespected, scared, uncomfortable, or secondary. 

What do you do when someone tells you they don’t want to be with you but want to keep flirting as if you’re still together?

Tell them clearly: “Since we’re not together, I need you to stop [flirting behaviors].”

If they refuse to respect this boundary, or argue that you’re being irrational, or deny that they’re doing it, stop spending time with this person.

Many people ask “How can I talk about polyamory to the person I like?” and I know the answer is communication. The problem is that I am 17 and kids my age aren’t very open minded. How can I tell a guy/girl what I like without being bullied?

I work with teens, and I can confirm that while they do tend to rebel against the status quo in many ways, teenagers actually do tend to be more conservative when it comes to things like gender roles, homophobia, etc. Online, you may find many young people who have very open minds, but the average teenager right now tends to have pretty rigid attitudes about how relationships should be.

There is no surefire way to prevent people from bullying you, and there is no guarantee that you can explain polyamory to a peer of yours and have them understand. Dating polyamorously in a culture that is hostile to it - whether it’s due to age, politics, religion, or another demographic - can be very difficult.

My advice to you is to read up on polyamory and develop a strong sense of yourself as a young poly person, so you are prepared to explain and perhaps defend yourself when people ask you questions. You may want to have some quick definitions and examples ready to pull out, and some “Poly 101″ resources to share with people who are more interested.

As a student, you can also use that to your advantage - if an assignment permits, you may be able to do research on healthy nonmonogamy and present it to your classmates! You could also see if there is an LGBTQ+ club on your campus that you could partner with to raise awareness about polyamory and host events for any student interested in “alternative” (as much as I hate that term) relationships.

When you like someone, it’s okay to be clear about what you’re interested in - “I want to date you, but also be able to date other people. It’s called polyamory, and I’m happy to answer your questions about it!” They might say they’re not okay with it, which is their right. But hopefully anyone worthy of your affection isn’t someone who will turn around and bully you over that. And if people do, keep your head up and know that as soon as you get into your late teens and early twenties, your world will open up to include a lot more people familiar with, and down for, polyamorous relationships.

Do you know of any poly advice sites where I can talk one on one with someone? preferably something free because i cant afford a therapist or something like that really but i’ve had a lot of struggles with my relationship and im new to poly relationships and have a lot of questions and wondering if im being irrational about things or if it’s very reasonable to be upset. i cant ever tell if something is ‘just a poly thing’ or actually wrong so i’d like someone to chat with about it all.

Here is my list of mental health resources, which includes general online chat rooms and other free or low-cost options.

Be very careful about using open online chat rooms or forums as a substitute for therapy. Take the advice that is healthy for you, and step back if someone is being judgmental or unhelpful. Here is a great post at The Polyamorous Misanthrope about tips for finding online support as a poly person.

That said, here are some places you can talk to other poly people and get more one-on-one advice about your specific situation:

You may also want to do some independent research into polyamory - lots of people have trod the same path you’re on, and you may find that certain scenarios you think are unique to you have been addressed in poly guides! 

Ok so I know polyamorous relationships don’t have to be sexual and/or romantic but is it fair to not love the other person and only be in it for the sex when they love you and they know you don’t but they say it’s fine? Do i make sense?

Most relationships that people interpret as polyamorous do have something to do with romance and/or sexuality - but you’re right, some people expand their polyamory to include emotional intimacy and committed partnership without any other connotations of “dating.” However, being poly doesn’t mean that you’re obligated to make all of your relationships deeply intimate.

Your question seems to be whether it’s okay to have sex with someone you know has stronger feelings for you than you do for them. In general, it is never okay to take advantage of someone or manipulate them - do not use their feelings for you as a way to get sex, or make promises you have no intention of keeping.

But if both parties are fully aware of the mismatched levels of commitment and affection, that’s a choice for the two individuals to make for themselves.

For the partner who loves someone who doesn’t love them back, they need to consider their own emotional safety. Are they sticking around because they hope the other person will someday grow to love them? Are they in denial of this mismatch? Are they settling for someone because they feel like “willing to have sex with me” is just about as good as “loves me”? None of those are healthy reasons to stay. But if they’re going into the situation with clear eyes and full agency, accepting that they have an unrequited crush but might as well get some fun sex out of it, who is anyone to tell them they don’t know what’s best for them?

For the partner who doesn’t love the other person but is still sleeping with them, they need to think about how honest they’ve been with themselves and the other person. Have they hinted at future emotional intimacy to keep the sex available? Do they do anything manipulative that might make the other person feel that they need to settle for a sexual-but-not-emotional partner? Do they feel good about the sex and the interactions outside of the bedroom? This person has an obligation to be clear with the other partner about expectations they can and cannot fulfill, so the other person can make a fully informed decision. They can also make the choice to stop having sex if they feel guilty or unfulfilled by it - but they should be careful not to spin it as a condescending, “you say you’re okay with this but I know what’s best for you” kind of thing.

Can you explain the types of polyamorous relationships? How many are there? Why can’t I find many information online? Polyamory seems awesome!

I am sorry you’re having a hard time finding much information online about polyamory! Here are some good places to start with an overview of the different types of polyamorous relationships:

You can find lots more resources in my FAQ here!

My SO and I mutually agreed to not have sex or anything with our outside partners, but she told me that she has been physical w theirs once but she regrets it and feels like they were pressured into it. her partner didn’t say she had to but it was more like a guilt trip, as it sounds to me. I’m not necessarily mad at her but I’m just worried she’ll do it again or something else feeling obligated to because her partner tells her she thinks she loves her a lot. I trust my SO but I’m worried that she’ll be manipulated into doing something she doesn’t want. I don’t know how to talk to her about this without it becoming a “you don’t trust me” issue. I don’t want her to get hurt, by me or her other partner.

I’m confused about how you define “partners” if you are not having sex “or anything” (which I assume means sexual intimacy). For you and your SO, what is the difference between an “outside partner” and a “friend,” and are all these “outside partners” clear on this definition? Everyone has the right to define their relationships in ways that work for them, but it sounds like this arrangement is pretty standard monogamy - have emotional closeness with other people, but not romantic/sexual closeness.

If your SO is spending time with someone who manipulates and guilt trips her into sexual intimacy, that is NOT OKAY. Consent must be freely given, and it is not healthy to be around someone who pressures you into doing something physical that you don’t want to do. You can tell your partner that you’re concerned about her and want to make sure she’s safe in all her relationships. It’s not about not trusting her - it’s not saying “I think you are going to cheat on me again” - it’s saying “This person did something hurtful and not okay, and I want to talk to you about whether you want to keep hanging out with them, and if so, why.” You can let her know you support her and talk about strategies for asserting her boundaries and getting out of a situation that doesn’t feel safe.

If you make your concerns clear, and she decides to keep spending time with someone you feel doesn’t respect her consent or boundaries, you can’t control that choice. You can decide whether you want to continue seeing someone who involves that kind of person in her life, or whether the stress of knowing she’s seeing someone she may be intimate with despite promising you not to is more than you can handle.

[CW: the following section may be triggering to anyone who has been pressured into physical intimacy and was victim-blamed afterwards. I have a policy of taking people at their word when they say they were not consenting, but in this case, I want to give advice that covers another possible scenario.]

Of course, all the above advice assumes that everything you told me is correct on the part of everyone involved. It is possible that she did want to be intimate with that person in the moment, but knew it would upset you, and is choosing to not take accountability by blaming the other person. Setting boundaries that are so rigid - you can be “partners” with this person but not be “physical” - can sometimes lead to people choosing to violate those boundaries based on desires in the moment. Maybe the other person did initiate, but maybe your SO had more agency in the choice than she is owning up to. She may regret it because she knows it was a violation that would upset the terms of her relationship with you, rather than regretting it because she didn’t want to do it at all.

It might be wise to have a talk about why you two have set this boundary about sexual intimacy and whether relaxing it might prevent the feeling of tension and pressure that comes with wanting to be with someone when it’s forbidden, which can in turn make someone feel like they didn’t fully want to do something even when part of them did want to. 

My partner and I got into a semi heated discussion about being able to love other people equally to your original partner. I’ve also had multiple issues with her being inappropriate in some way with other people. I really don’t want a poly relationship, especially when her extras are hidden. I’d be open to us choosing to find someone together, but I can’t help but feel this is wrong to deal with.

There is a separate issue in just about every sentence here, so I’ll try to break this down.

When you say you had a heated discussion about “being able to love other people equally to your original partner,” what made that discussion heated? Do you believe being able to love multiple people in the same way is impossible while she believes it is? Why did this difference create so much tension - is it possible that both of you may experience love differently? Is the argument about whether such a thing is ever, objectively, possible, or whether it’s possible for you? Remember there’s a difference between “I can’t do that” and “that is not possible.”

When you say she has been “inappropriate” with other people, what does that mean? Is it behavior you consider cheating or borderline cheating? When you got upset with that, how did she react? Is she trying to stay within the boundaries of your relationship, or insisting that what she did wasn’t inappropriate and you need to get over it? Do both of you agree on what you two have a right to ask and expect from each other?

You say you don’t want a poly relationship - that’s fine! If your partner does want one, that might be a problem. One of you will need to make a compromise, or you may need to decide not to continue this relationship if she wants to be poly and you do not. When you say you especially don’t want a relationship if her “extras are hidden,” does that mean she is currently seeing other people without your consent and hiding it from you? That is cheating, not polyamory. Or does it mean that what she’s proposing is a “don’t ask, don’t tell” kind of open relationship, and you’re not okay with it? If you’re not okay with something, you don’t have to do it.

I’d caution against “finding someone together” - that is called “unicorn hunting,” and while it can work well for many people, it doesn’t go well if all people aren’t on the same team. If you’re only agreeing to this because it’s something you can hold your nose and stomach, and you still don’t want her to care for anyone “equally” compared to you, that creates a bad situation for the person you try and date together. If you’re not feeling like she respects your needs in a relationship and you don’t want to be with someone who sees other people, and she insists on doing this with (poly) or without (cheating) your consent, this may be a relationship dealbreaker.

Is it okay for my partner to be thinking about other people when play and stuff? I get really upset when I know he’s thinking about another partner or even just thinking about someone else he knows/has a crush on because I feel that’s disrespectful to me? I have never and would never think of someone else while we were playing because I feel it’s so rude and disrespectful to the other person? Is this silly of me or what should I do? Do I need to be more accepting?

What I’m confused about here is how and why you know your partner is thinking of other people while you’re playing???

On the one hand, no one can fully control their thoughts. Sometimes I think about other people during sex, or other completely unrelated things. But the last thing I would do is tell my partner about it! There are some thoughts that are just tactless and unnecessary to share. 

I don’t know the context for how you know this. Maybe your partner thinks it’s hot to talk about other people while playing - fantasizing about threesomes or cuckolding or something like that. In that case, you need to let him know that you don’t like that kind of talk, and he needs to explore that fantasy with someone else. Maybe he has a severe level of oblivious tactlessness that makes him think it’s a good idea to say “this is how Gremily likes it” or “Clodeline taught me this move.” Let him know that bothers you and ask him to stop. If he’s doing it out of cruelty or manipulation - if you suspect he’s just bringing it up to make you insecure, or just saying rude things he knows make you uncomfortable - stop playing with this person and dump him immediately. 

If he’s not actually saying anything, and you just have a sense that he’s thinking about someone else, that’s a different issue. Sometimes people include their internal fantasy life in their sex life, and that’s just a reality of sex. If he’s not making it your business, you may need to drop the issue. Do you ask him if he’s thinking about someone else? Are you interpreting some of his behavior to mean he’s thinking about someone else? That may be a manifestation of insecurity on your part rather than something he’s doing. Remember that unless you’re psychic, you don’t actually “know” what’s going on inside his head. If you consistently find yourself feeling disrespected by what you’re convinced other people are thinking, you may want to think about seeing a therapist to help with those kinds of thoughts. 

When asked a similar question from the other perspective, the advice columnist at Dear Prudence replied:

Ever see your wife close her eyes during lovemaking? If so, don’t ask, “Am I Channing Tatum now?” Thank goodness there’s a hard, impenetrable case around the soft substance that produces our thoughts and our sexual fantasies. There’s a reason evolution did not result in subtitles being projected across our foreheads so everyone can know what’s really going on in our heads.

I’ve been dating my partner for about two years. when we first started dating they said it was okay with them if I ever got crushes on other people, but it was never brought up again. now I’ve met someone new who likes me back. I still want to be with my datemate, but I also want to date this other person. the only problem is, I know I’m not going to be comfortable with it unless they’re dating each other too. how should I initiate that? I’m not going to force it, but I want to at least try.

You can’t just ask that two people date each other because it would make you comfortable. Even “initiating” without forcing it is a pretty big leap considering you and your partner haven’t discussed being in a triad together, you only briefly talked about having crushes on other people, two years ago.

You need to talk to your partner about how they feel about polyamory. When they said it was okay if you had crushes on other people, did they mean it was okay if you acted on them, or just that they don’t mind you indulging in the attraction of a crush? How do they feel about you dating vs. sleeping with other people? If you do see other people, how do they feel about hearing/knowing about it?

The conversation should start in the abstract so you can get everyone’s feelings out in the open - my advice would definitely NOT be to open with “hey so there’s this person I want to date, so I want you to be okay with that, and also I want you to date them too!” - that is a pretty massive thing to drop on someone and requires excessive emotional leaps on their part. This means you may need to put the brakes on whatever is developing with this new person while you and your current partner work out needs and expectations for transitioning your relationship into new territory.