Parents doing lot of interference want file divorce and child custody

Hi .. me and husband having quarrels because of their parents interference in our married life due to which I went for a job in Bangalore when my child was 3 year old . There is no one to take care so we both discussed and decided to leave my kid in my parents house in hometown(my in-laws refused to take care of my child), we both visit weekly basis . Now my kid is 4 year old where my husband blackmails me for a divorce or taking my kid without me to his house(my in-laws never fed him food or taken care of my child right from birth.whenever I ask them to look after for even 1 hour , they refused. My son is also not comfortable staying there without me as they scolds,beats and doesn't give proper food to him). Pls help me what should I do now ? I want to save my kid's life and our married life as well.