My fiance has a daughter and a son that he adopted from his BM. He has full custody of his daughter and fully adopted his son. He's a good dad. They live with him.  he tries to full fill my needs but,  Since we got engaged I've been rethinking my decision. I am really confused and very frightened that I'll regret my decision. he wants us to rent a place and live together before we get married,  so that I see what it is to be a co-parent. I've discussed my fear and doubt with him but all he says is I need to be positive and just believe that things will be okay.