My fiancé and me are together for 4yrs now. We both have 2 sons from previous marriages, and a girl together. He got custody of his son in his divorce and she has visitation, she got married and also have a girl with the husband. The time we are together we have lots of problems with his son and it only gets worse, we phoned his mother to ask that he go and live with her, but the excuse is that they don't live near a school and its not her husband's responsibility to care for her son. She doesn't give any financial contribution and in the last 4 years she saw him about 4 times. I now its my fiance's responsibility, but our relationship can't handle this anymore. How can we make her to take her responsibility toward him?