Husband and in laws threatning to take my child

I got married in december 2010 and mine was a love marriage..Hardly after one week of getting married my in laws have started to torture me mentally as well physically in every way possible.My husband first use to take my side as he saw and knew how his family was ill treating me and my family...My family said everything will be alright and i should be patient and compromise as life of a girl goes on that way.But as the mental harassment was unbearable i left ny in laws place during 2012 with my husband's consent and during 2013 we had a baby boy.My husband reassured me that his parents have changed since the baby and they wouldn't behave like before and forced me to come back live with him which i did on nov 2014 but hardly 6 months passed things became more and more worse now my husband along with his parents sisters and brothers have started harassing me so much now that i have gone into depression and don't want to live with them anymore.As i couldnt bear the torture of every single member of my husband's family i again left my in laws house for a month and went to my place and told my husband to keep me seperately away from his family, he along with his parents came to our house and abused and insulted me.My husband slapped me in the middle of the road and forcibly took me back to his place as he is threatning me saying that he will take my child away from me and will get my younger sister also divorced by telling her husband false stories about her character..I am very much helpless because i don't want to live with my husband anymore.Just because he is threatning to take our child i dont know what to do. My in laws are financially rich and influential and if i file any case against them they will do something and will win the custody of my child which i dont want at all..Please help me sir i want to get a divorce from my husband and keep my 2 yr old baby boy with me.