He still doesn't want me!!!?

I know what my problem is but what is HIS problem. I am the greatest girl friend he has ever had. I care more for him then any of the other tramps in his past, and all I want is to make him happy. So why WHY WHY WHY doesn't he want me. He has told me before that he doesn't understand me because every time he hurts me I come back. I am still there for him as a friend, and I still want to be that girl. He said he didn't understand me I told him he wasn't suppost to. But what the hell....he knows all this and yet still he will not let himself be happy with me. EVEN his family who don't get a **** about much of anything in his life say I was the best girl friend he has ever had....WHAT GIVES!!!