annoying teenage drama help

Last year was my last year of high school and i fell in love for the first time for a guy that has nothing to do with me. I dont feel the need to date him. The thought of dating anyone actually makes me uncomfortable, so all I wanted was to be his friend. One year later since the first time i talked to him he was venting to me about liking a girl that didnt like him back and mentioned that he knows i like him and apologized. Its ok to me since i didnt even want to date him in the first place, and we're very close friends.

Even though i dont want to do anything about my feelings for him it still hurts knowing he likes someone else (im learning to deal with it and it used to be worse) but its whatever. The problem is that the person he likes is a long time friend of mine. They hit it off really well and are on good terms again. Theyre very clingy and stuff.

I've been feeling really bad bc this friend knows what i feel. She apologized to me for flirting with him months ago, and hasn't told me that they've been going out for a long time now. Her life is not my business but i cant help but feel a bit betrayed.

I've been trying to deal with this, but now that theyre on good terms again he wants to bring her along to our friend group's outings. The atmosphere between me and my friend has been bad, she never told me about him and despite everything i've said before it hurts seeing him with whos basically his girlfriend right in front of me. It sucks really bad because i love them both deeply and i don't want to make him feel bad for me or anything but i don't see how i could possibly get out of this situation without telling him that i don't want to see him with someone else. What am i supposed to do?