I'm in a monogamous relationship, but there's someone else in my life I have strong feelings for

I'm in a committed relationship with someone and I know he has plans to marry me. There's another guy I've been friends with for a while and he split my last relationship up (not intentionally - I realized I had really strong feelings for him and we ended up having a little bit of a thing going on, which my ex found out about.) I still love him and always have the urge to kiss him. How do I tell my now partner. Am I poly?

I can't tell you whether you're poly; that's up to you to figure out! I have an FAQ page about that here.

Some people in monogamous relationships do have feelings/urges for other people, and consider it part of their commitment to their partner that they choose not to act on those feelings. Only you can decide for yourself whether having feelings for another person means you should try to change the terms of your existing relationship, or whether you need to take some space from that other person and accept that monogamy often requires work and sacrifice, just like polyamory.

Or, you can decide that these feelings are not something you can, or are willing to, ignore. In that case, it's worth bringing up with your partner. However, be prepared for the possibility that your partner is unwilling to be in a non-monogamous relationship with you. In that case, you'll need to decide how to act on that information from him. If it's a dealbreaker, you'll need to leave the relationship - it'll suck, but at least you learned about this incompatibility issue before you got married.

If you want to say "okay, now I know where you stand, I'm glad I checked," and continue with monogamy, be prepared for your partner to wrestle with some insecurity or jealousy, since this is being brought on by your strong feelings for someone that you've already shown a willingness to cheat with, or leave another partner for. This is a pretty fraught situation, and you'll need to really clarify for yourself whether this is about you realizing that you have the ability to love more than one person and want to be able to pursue that; or you realizing that you just really, really want to be with this one specific person.

It's entirely possible that your friend wouldn't want to be your second partner; or if you leave your current partner for him, that things wouldn't work out with him anyway. Try to maintain clear lines between "I want to try non-monogamy" and "I really want to date this particular guy" and know what you are, and are not, willing to sacrifice to pursue one or the other.

How do I know if I’m mono or poly if I’ve never been in a relationship before? Like never even kissed someone or gone on a date??? Like I’m 17 and I’ve only ever even crushed on someone once so how do I know

You don’t have to! Being 17 is a time to experiment, to try different things, and to find out who you are.

Our society, and especially the world of online discourse, likes to focus on identity labels. Am I gay? bisexual? ace? gray-ace? demisexual? female? male? genderqueer? what fandoms am I in? what music do I like? 

Relax. You don’t need to have the right, dictionary-perfect terms for everything you are and everything you want right now. Or ever, for that matter.

What you need to know is what’s healthy for you right now. What kind of relationships are you interested in? What are boundaries your partners can’t cross? What emotional needs would you like a partner to meet? 

The point of identity labels is to help you develop healthy relationships and boundaries. Let that come first - get to know yourself, and then if certain terms feel right based on what you learn, try them on.

For now, and for always, you don’t need to have a tidy little tumblr-bio list of labels, you just need to live authentically as yourself. 

To quote Tim Manley:

“As an easy explanation, I identify as bisexual. In certain circles, I prefer the vagueness and openness of the word “queer.” With myself, I don’t need a word.” — Tim Manley, interview for solo show Feelings

Get to where you don’t need a word with yourself, and the rest will come. 

I was recently told about Polyamory by a tumblr friend. At first, I was hesitant because I thought she was referring to just polygamy. But as she told me more, I become very curious and liked everything I was told. I’m wondering if perhaps I am poly…? Before I get into every relationship I caution my partners that I will likely flirt with other people, but they shouldn’t be worried. Also, I always find myself inclined to end relationships because I form crushes on other people.

You might be poly! You might not. I’m just an internet advice columnist! If in the past, you found yourself capable of crushing on multiple people at once, polyamory is definitely something worth checking out! Try reading The Ethical Slut and More Than Two, and checking out online resources explaining and introducing polyamory.  

But remember that polyamory is not a cure-all for relationship problems. If you left relationships in the past because you got bored with them, or found yourself sabotaging them, or if part of the draw of flirting with other people is seeing your partners jealous - those are things to work out with yourself before drawing others in. In general, I think poly is a pretty awesome, healthy way to be, and I wish you good luck in your explorations!