What to do if the husband is harassing me repeatedly

I have been married for 7 years now. Since, the marriage it was trouble. My husband harasses me mentally. in the early phases of marriage, He used to tell me that he married me because of his mother who forced him to do so and he scolds his mother. He also said to return the thali and go back home. He also left me in the railway statement in the mid night after a fight all alone. I was pleading him not to leave me, but he left. He gets angry uncontrollably. He blames me for everything. If there is traffic jam, he blames. If kid is little cranky, he blames me. If kid supports me, he starts abusing kid also. He shows face everytime when he comes home and keeps blaming me everytime and scolds me. He threatens me saying that he will snatch the kid from me and he will leave. In case if my parents come to stop him, he will kill them. All this is increasing my tension day by day. I am staying with him only because of kid. I want to get out of this marriage. But, I want my kid also.Please help