Get this sorted BEFORE you marry. My wifes ex is not my favourite person on this planet, but he is my step daughters father. I have always encourages both of my girls to spend as much time aspossible with their father. Until the day that their father hurts or harms them in any way, it should be up to the kids to make the descission. Chat with him and remind him there is one rule and only one rule to abide by. The kids come first!!!!