Well, you DO have control over your schedule. I wouldn't change it. ESPECIALLY if he is going to move in with her. They need the same routine as much as possible. If he wants to change it, he can take it back to court. Until then, it's a done deal.
Focus on your life with the kids. Talk with the kids about how you feel about the issues with him living with her. For example, if he is living with someone that he is not married to, and you believe that is not right, tell them why. Use it as a learning experience. I think they already know he made bad choices...leaving his wife was a bad choice...they can understand that what he is doing is another bad choice. If they don't like her there, they can tell him that, and they SHOULD. And, if he gets mad at them, give them some words they can use like "I need to tell you my feelings, Dad. My feelings are never wrong."
