I can't see the way out

I've had a very difficult life: lack of money, lack of friends, a very complicated family (divorced parents, father who doesn't care about me, mom who's not wise and dates jobless junkies, uncle who is a junkie himself, gets drunk and beats me and my mother), neighbours who judge my by the family I have, and a boyfriend that is all I have in this world but doesn't support me at all (although he says he loves me), keeps criticizing me for stupid things (that I should dress more simply, that I should have a different personality - he says I want to be more and better than I really am - of course I do, why on earth are we here for if not to be each day better?), he keeps saying (in a joky way) in front of other people (specially in front of his family) that he's going to leave me and switch me for another girl, keeps reminding me how different we are from each other and making me feel guilty about that, almost doesn't kiss or hug me, when I try to hug him or kiss me he avoids me and say I'm suffocating him.
He's destroying my self-asteem, I'm trying to get over everything wrong that happened in my life and that is not my fault (lack of money, disfunctional family) and trying to build my own with my own efforts -and it is so hard - and he's not helping, he's only making it more difficult.
I already asked him why is he still with me if he thinks we are so different from each other and he says he likes me and that he has pitty of me for all that I've been through. I told him I don't want his pitty and everything I'm telling you guys I already told him.
I know that maybe we should split, we're not making each other happy anymore, but I can't do that regarding that I have no one else in this world (we´ve been together almost for 3 years). This may sound stupid and most of you may respond "get yourself a life". Easier to say...