I never had a relationship before. Now I have a boyfriend for a year and we are on a non-monogamous relationship. He has another girlfriend. I don't get jealous very often, but they really like going to group sex parties. I never tried going to this kind of event, and I don't really feel like it, mostly because I think I am demisexual. But I always feel really bad when he talks about going to such parties. I tried talking about it with him, and he always asks what exactly bothers me about it. But I don't know how to answer. I just feel very bad and sad, and get mad with myself for feeling like that and not knowing WHY I feel this way.
I can’t figure out for you why this bothers you, but I can suggest some time alone to think about this, and journal about it if writing things down helps you. “Bad” and “sad” are pretty vague feelings - can you do more to identify how you feel? Left out? Confused? Disappointed? Jealous? Annoyed? The more precise words you can find, the more you’ll be able to understand and address those feelings.
On a personal note, I have a theory - I don’t know you, so I’m projecting and assuming a lot, but here goes. I am a horrible dancer, I don’t enjoy dancing, I have a learning disability that prevents me from understanding musical rhythm, I’m not very coordinated - I don’t dance. One of my partners is very musical and athletic, and he does like to dance. For a while, he was dating someone who was also a dancer. They’d go out dancing together, and through her he got connected to the dance community in our area and learned a lot and had a lot of cool experiences.
This bothered me a little bit! He was out there having experiences that I couldn’t share, with someone who offered him something I couldn’t. And it wasn’t exactly jealousy, because it wasn’t like I wanted to be out dancing with him. I certainly did not! I didn’t necessarily feel threatened by her, since we were very comfortably polyamorous and I didn’t think he’d leave me for her so he could pursue a 100% dance lifestyle or something. But I did feel…kinda bad…because feelings aren’t always simple and rational!
An important thing to note here is that thinking through it all didn’t turn off my icky feelings. Not all feelings can be completely rationalized away. What they did was help me choose how to respond or act on them. Not everything is totally comfortable. We are all capable of experiencing unpleasant feelings without dying. My boyfriend is not obligated to never ever do anything that causes me to have a feeling I don’t like. It may be that this just isn’t a thrillingly joyful thing for you, but just like going to work on Monday mornings, it’s something you can experience without it ruining your life.
So it’s possible that what bothers you about this is that it’s something you don’t see the appeal in, and can’t join in. It’s something he’s sharing with another person that you just can’t share with him. Shared experiences are the foundation of any relationship, so that can be a really tricky, difficult feeling. What I did with those feelings was mostly challenge and reframe them. What I like about polyamory is that my partners can seek out experiences that don’t require me; I would much rather him be out dancing with other people than pestering me to go dancing with him and being annoyed and resentful when my unwillingness robbed him of an experience. You would probably prefer him to go do these sex parties with someone else and then spend his time with you appreciating what you two do have in common, rather than being disappointed and bothering you about it. It also means that when I am into something that he isn’t, I’m free to pursue that experience with other people. It goes both ways, and I benefit from both!
It is possible that you just feel kinda icky about the whole thing in ways that you can’t entirely smooth over with self-work and re-framing. It is totally okay to ask your partner to keep the details of these parties to himself. If he wants to go out to a sex party with his other partner, he can let you know ahead of time that he has plans with them, and you can plan to spend the night doing something you enjoy. And when he gets back, he can find something to talk about besides the specifics of the party. He doesn’t have to hide or lie, but he could also be sensitive and discreet. That’s a completely reasonable balance for a couple to strike. You don’t have to set forth an entire psychosocial treatise on why it bothers you for your partner to agree to this, and if he demands that you explain or prove it completely, he’s not being healthy or fair.