I'm lost... And hurt...

My husband and I have been married for almost a year and we have a 3 1/2 month old baby together and during the whole pregnancy and everything it was amazing and then after I had him he started treating me like shit for no reason. I am no longer pretty enough for him I look horrible to him because my tummy sags now. He calls me names all the time to hurt my feelings he hits me not enough to bruise me and pushes me around. I want to leave I'm done being treated like this. But I'm scared that if I do he will try to take my son away from me. I have a domestic violence charge for false imprisonment because I tried to take his keys away after he pushed me when I was 4 months pregnant. I love him I want him but I'm tired of being treated like this by someone who says they love me. I'm sorry this is long. I need advice please.