Do you think the abuse will get worse? what should i do?

I have been with my boyfriend 8 months i am 21 and he is 25, My boyfriend had a bad child hood and he is a big drinker. My boyfriend has a anger problem and has always been emotionally abusive and punches walls and stuff, He always said he would never hit me, but lately he has been raising his hand to hit me, pushing, smacking me over the head not over hard, twisting my arm punching me in the leg, He seems to think im cheating on him and don't care about him and all this stuff. I don't really want to leave him because i we do have a good relationship and he does every thing he can for me. but lately when i go to leave him he has kinda been making threats saying im gonna do this and that which worries me because i feel afraid to leave him if i want to.