Why is he doing this to me. This is a great question for males?

I became friends with a guy who is with someone else and it is on the brink of breaking up. We have never messd around but have always been friends. I get emotional at times and we get into arguments but he always talks to me and we end up working things out. There have been times though where he doensn't speak to me for a couple of months. And he told me that me and him will never ever be together because he wouldn't be able to take it if I were to do this in a relationship. We do get along excellent except for these emotional upsets that I have and he gets furious when this happens. So, first he says that me and him will never ever be together becuz of this. Than he says if me and him were together and I did this he would never speak to me again. So, if we would never be together y does he say the latter? I am confused because we are totally totally attracted to each other and there is so much ual tension between us but he says this? why?