He's Dr. Jeckly & Mr. Hyde depending if his child is w/us for visitation. Help w/advice/insight please!?

My two sons and I have been living with my boyfriend for 18 mos. now. I love him dearly and am grateful for more or less supporting us three. I was with him for a grueling 12 month custody battle %26amp; in fact helped with his legal work. He got what he wanted with my help. The problem is that he's Dr. Jeckle when it's just he, myself and my boys but quickly becomes Mr. Hyde once his daughter is with us for visitation. Example: When it's the four of us, there's a routine and even tempered attitudes in the household. In other words, things are good for the most part. But as soon as his only child (a girl) is over with us, my guy's attitude changes and it becomes he and his daughter against my boys and me. It hurts for this is not healthy. I even read a book about step-parenting to help me understand this behavior. Example: He still expects my boys to follow rules and have consequences if necessary; but, his daughter can do NO wrong! Inconsistency %26amp; confusion. What am I to do? HelpHe's Dr. Jeckly %26amp; Mr. Hyde depending if his child is w/us for visitation. Help w/advice/insight please!?
Whoa! That's really a complex problem. I never thougt something like that would ever happen to a family. Anyway, why don't you seek a professional help for that one? A family counselor perhaps?

beauty