It definitely sounds to me like your daughter has a problem with at least the bathing together. I agree that you should check with your custodial agreement and see what can be done about this. Does your ex have any explaination as to why he decides to sleep over at his girlfriend's place when it his time with your daughter. I also agree that time should be reserved by him for his daughter, not a good time for him and the girlfriend to be together. It seems, in this day and age, that if he were really serious about her, they'd either be married or living together. Since they are not, I'd be a bit dubious as to whether this relationship is going to last, and in that case it definitely is not appropriate for them to share baths and a bed. I see no problem with him having get togethers with them, go out to dinner, to a park, or whatever so the girls can get acquainted and your daughter can get to know the girlfriend as his friends. Then if they do get married, your daughter has at least some idea of who they are. But I agree with you totally if you try to get it worked out to the point where he cannot take her there for overnights at all.