Husband cheated me hiding first marriage

Hello sir/madam, My marriage was on sep 2015,i have completed my mphil in commerce.i am home maker,he is working in canara bank,and now i have a boy baby 8 months old.i came to know my husband got married before and got divorsed too..but,i dont know about the before marriage.. From the day one of my marriage my mil and sister in law always make issues,we were in mglr after marriage,wen ever i came to their place they will make some issue. And wen they hear that i was pregnant they got more anger and i went there for first pongal they fought with me pushing my hand,and pressing my stomach saying let the baby inside die..so i inrefused to go to their place from that day.my husband alone came and asked for sorry and took me there again to mglr..and while returing from mglr on may.he called me to their place but i refused,so he used very bad words against me..behaved very harsly and left infornt of my moms house and went..as such again for valakappu my father went n asked them to make the function good..like this they torchered me mentally.,so i made him to right in a paper that my husband is whole responsible for me n for my child inside..he too wrote n signed. Wen i came to know abt first marriage,my husband accepts the truth.but my mil and father in law n sister in law came for compromise.but they talked abt me badly n went.till now no phone call,no message from them..husband alone came n asked for sorry.and said he will buy a house n he will take me nu.but now he is telling he will send me divorse and he wants my kid too.. What ever they did i was not making it an issue..they hide their first marriage also..even then i was ready to live with him if he comes out of their home..now last week he messaged my father very badly..like still y u r living go n die nu..and many words very badly.. And now that i dont want to live with him bcoz he spoke very badly abt my father.i want to complaint about them.and i wil not give my child to them.. Plz suggest me what should i do now..i am becoming mentally very weak..