I Cant' Leave Him

I have been with my boyfriend for about a year.  He has always been mean to me.  He calls me stupid, and that im no good for anything.  He has even hit me a couple of times.  When he's not mean, hes is the most wonderful person i have ever met. But he expects me to do everything.  He doesn't understand that I have a full time job, and go to college.  He calls me lazy and expects me to drop what im doing and help him.  He will tell me that he will make dinner, but later yell at me for never making dinner.  I don't understand.  I told him that when i started school that homework will come first.  But all he wants me to do is stay at home and clean and cook for him. I just hate him.