Don't know what to do

I'm almost 100% positive that I'm going to end up being single before my baby is born. From the looks of it were both not happy. He's always throwing me down, always calling me names, always leaving me in the house alone so he can go attend to his friends and his brother that I can't stand. I'm not the type to sit here and take someone away from their family cause I wasn't raised like that but last Friday his brother tried hitting me and he got in my face screaming at me cause he was drunk and I had to defend my self alone. I told my bf and he got mad but instead of him talking to his brother about the situation and telling him that he was wrong he goes and kisses his ass. That to me was a slap in the face because if my sister or my brother was to do that to him I would cut them off in a heart beat. The only time he's nice to me is when he's high off of his weed. Yesterday I could've even sleep with him because I hate that smell and he has the odasity to call me childish. It's an argument everyday, name calling everyday. It made two to make this baby and I feel like I'm going to be in this alone cause he wants to be up his friends and brothers ass. I won't leave him at this moment cause I know if you want something to work you have to try to fix it before just leaving it but how much more can I take. And due to my family problems I honestly have no one to help me. My mom abandoned me when I was a baby and my dad doesn't want anything to do with me because of his new young girlfriend. Living with him is the only place where I know that I'll get a meal for the day for the baby but honestly I would just rather live at the park and die slowly than to be living here with this heart ache and constant reminder that I know it won't work. What should I do ... Leave or just stay?