Why Do I Keep Falling For Straight Guys

So it started off one day when i meet this guy who goes to my school we were at a basketball game and we just talked the entire time forgetting that there was even a game going on, like it was to the point were he stayed an extra hour just to talk even after the game ended. So fast forward two months and we become really good friends, we hangout after school sometime, eat lunch, and even text right. He's extremely good looking and has a nice personality but the thing is that he's straight (Im in the closet by the way and he never told be he is straight but he talks about girls he wants to fuck sometimes). I know that a lot of you guys are gonna tell me why cant you just have a guy only be your friend but the way he looks at me and opened up to me left me lovestruck. I hate the fact that he wants me to open up to him and become a bestfriend to him but I really cant do it anymore play along and then get shot down by reality. I need to know what you guys think about this