You've been together a few months....and you're this twisted, bitter and jealous??
If I were him, I would run away.
This is going to eat you up, OP and I get the feeling that if it wasn't this woman, you'd be fixAting on some other imagined slight and making yourself miserable.
Life doesn't have to be this hard!
Do you really want to be this bitter, snipey person? No? Well then, walk away! Do things that make you happy. Then maybe, MAYBE you'll meet someone else and the both of you could make each other happy.
You've locked yourself in to this, I think, primarily because you feel you "should" have a boyfriend at this stage of your life. It's not true.
Get yourself some other interests and passions other than watching a green dot next to someone's name flick on and off.
It's not going to get any better than the early "honeymoon" period. This is it. This is your "honeymoon". And you're fucking miserable.
Don't waste your life.