My boyfriend thinks hes gay...

Right now i am more miserable then I've ever been in my life, the guy I am painfully in love with and have been going out with for almost a year now told me yesterday that he thinks he might be gay. He had said the same thing to me about two months ago but a few weeks later he told me that it had only been a phase he was going through and that he was over it. Now hes telling me that he no longer loves me even though he still cares about me, and he just isnt phsically attracted to me anymore. He said that what he told me two months before was true but he had lied about it being only a phase. I'm the only girl hes ever loved, and before he thought he was just bisexual but now he thinks he isnt attracted to girls at all. It's really complicated and i know hes extremely confused about his sexuality right now, and even though we are still going out, we no longer kiss, make out or do anything else physically with eachother. A week before we had gotten into a fight and hadnt spoken to eachother at all since yesterday, when he told me about him possibly being gay. I'm really worried he might be right and i dont want to lose him as a boyfriend, but how can he know hes gay when hes only 15? Could this possibly be a phase hes going through like he said before? Please help i dont know what to do...