Legal notice received from lawyer stating that my marriage is void and

I have got married to my husband last year who is aware of my complete past about my first marriage and love in my olden days. Every family person of mine and his and other society members are aware of my past life and he himself contacted us said that he knows everything about me and said he likes me so he want to get married. After marriage they started torturing me for extra dowry to clear their debts.. And sent me back to my parents.. Now he has sent a legal notice stating that we didn't inform anything about my past and and he says that I have both pre marital and post marital affairs and also I have tortured them for money it seems. I accept about my pre marital affair which every one knows but I don't have any post marital affair.. Legal notice stated that if we won't settle this in 1 month then they will go to court with civil and criminal cases.. He also filed that my first marriage is not dissolved so marriage with him is void.. But my first marriage is dissolved legally. H