Why does he do it?

Why does he do it, he's been through a lot.With family,friends,and his girlfriend i just don't understand.With every cut, drip of blood, and eventually scar, it often makes me wonder. I ask him why he does it, i tell him that i care;and each time i always get the same answer;it makes me feel good, it takes my pain away.if i try to help him he tells me not to worry and pushes me further and further away.I tell him that if he needs to talk, that I'll be here for him.So as we sit here and discuss his past...fears...and worries,i tell him that it'll be ok.He tells me that he'll get some help,and that he'll try to quit.Deep inside i want to believe him,but for some reason i can't. Now he doesn't do it as much,but the question still lingers in my mind, why does he do it??