Mental torture from in-laws and not from husband

Hello there! Ours is intercast marriage(different subcaste in HIndu). Firstly we did register marriage as both our parents were against it. We tried to convince them but nothing happened. Then in Jun'15 , we did traditional kind of marriage in temple with the help of friends. We both were working in MNC IT company. Then again we tried to convince our family saying that now we are officially married and begged for their acceptance. Eventually, my family agreed but husband's family is still in strongly opposes. I haven't lived with them as they are not accepting it. me and my husband were staying in Pune as our job was there. Mother in law and sister in law uses every possible bad words against me every time they call their son. My husband smtime ignore and smtimes gives reply. Now me n my hubby are in USA for some yrs. and I am pregnant but still my in-laws continues to defame me, my family, do mental torture, uses abusing words and forcing him to come back there. Take divorce from me and remarry a girl from their caste otherwise they will die. I am in too much tension as I left my job and I am pregnant. How can I save my marriage? My husband is only son to his parent and if situation becomes tense, we have to come to India. And at that time they will do anything to break our marriage by any means... plz suggest me some actions which I can do being here or there.