Me and this guy like each other but he is also in a poly relationship. I want to date him but i don't want to have to "share" him if that makes sense. We really like each other though. How do I tell him I don't want to date him if he is also dating other people?
You can just tell him that: “I really like you, and I would like to date you monogamously, but I don’t want to date you if you are also dating other people.”
Then, he can do what he likes with that information. He may say “then we aren’t compatible - bummer!” or he may say “then I’ll leave my relationship for you!” Either way, you’ll have your answer.
People say this to me all the time - it’s a pretty common situation. It’s very possible that he doesn’t want to leave his polyamorous relationship for you, and that’s his decision to make. It’ll sting, but you’ll live - nearly everyone has been through the pain of liking someone who can’t or won’t date them for any number of reasons.
Best of luck finding someone who wants a monogamous relationship with you, whether it’s this guy or someone else!