Legal Question in Family Law in Texas

Well, he could, but yes, he'd be in violation of the custody order. If that's what he wants to do and you don't agree with it, make sure that you give him something in writing pointing out that doing that would be a violation of the custody order and that if he does it anyway, you'll take him back to court over it. That way, he at least can't try to argue that there was some "understanding" between the two of you that his move was fine with you or that he forgot about that provision, and with some judges and in some circumstances, what he does after that might actually get him held in contempt if you do decide to go back to court to enforce the order.