I need someone to talk too..

I had my daughter September of 2016, my life changed forever. My delivery didn't go as we wanted too. My husband has another child with another women and his son has a bleeding disordered and a liver problem as well. So anyways, my MIL keeps asking when we are going to have another baby, I try not to talk about it around my husband because he is dead set on not having another baby. Everytime the conversation gets brought up with him in the room I start crying because I know I want another baby. I'm just lost on what to do. I want another but I'm afraid it's going to tear my marriage apart..