In love with a (probably)straight guy.
I am a 20 year old male, gay, and I am hopelessly in love with my roommate of three years. He, unfortunately, has all the symptoms of straightness. Most importantly, he has a girlfriend who he loves to have sex with.. I think. Through the years, he has become my best friend. He knows I'm gay and I have accepted that I shouldn't look for a relationship in his direction. That was all nice and fine until school let out this summer and we decided to rent a house together. His girlfriend took and internship in another state and he sees her maybe once every two weeks. Since the beginning of May, he has started to act really flirty with me and unfortunately it is working and I'm starting to fall for him in a way I haven't in a few years.
He always sits next to me with some part of his body touching me. Sometimes he randomly grabs me from behind and tells me he loves me. Sometimes he'll just sit in my lap. He gives me a lot of attention and the first thing he does when he gets home is find me and ask me what I want to do with him that afternoon. A few days he opened up to me about a couple of things he never told me before including that he didn't want to go see his girlfriend this weekend. He said it was too much of a hassle and he'd just rather stay here.
Anyway, as the weeks wore on, I started to get more and more hopeful about the possibility of something forming between us. Then all of a sudden, two days ago, he withdrew. Then his girlfriend came over to surprise him and he spent the whole weekend with her making sex sounds in their room. I hadn't realized that I had gotten so attached to him. It actually hurt me hearing those sounds on the way to the bathroom.
What should I do? I don't think I have the will power required to avoid him. He'll sense it anyway and try to get me to go out with him or something which I'll do without thinking.