Rules around the house

She said if he wanted her off the computer he would have to ask her. If he made a rule that no one should be on the computer of anyone else, he needed her to help enforce the rule.
That is the big problem, he or he and she establish rules of the house, but she does not follow through in helping to enforce those rules. She is breaking the rules as much if not more than anyone else.
How does he get her support?