I married a widow who has children. What is my role as their stepfather?

Your role is to be a loving protector and guide, without forcing yourself to replace their birth father. Treat them as a trust, because being good to your wife's children builds love and reward. If their father is still alive, do not block the children's relationship with him; support that bond with an open heart. Give attention and spending sincerely even though, under Islamic law, their maintenance (nafkah) is not your obligation, because such kindness will not be forgotten. Spend time playing and learning with them so that a sense of safety grows. Discuss with your wife how to bring them up so that the two of you are on the same page. See children in the family.