That's a very difficult custody arrangement. It's hard to see how you stand a chance at consistency when there are huge gaps between visitation and it must be tremendously difficult for SS. If I understand you correctly SS is with his mother for 9 months, or however long, and then with your DH for 3 months? Does he have visitation with his mother while he is with you? My 4 year old would be distraught at being taken away from me to live in another house for a week let alone months.

You might want to consider that his behaviour may not be down to getting zero discipline at home, it could just be that he is genuinely disturbed and upset by being passed back and forth between 2 homes for large periods of time. I can't imagine how confusing it would be for a child that young to have 2 carers with their own habits and rules for one chunk of time, then a different 2 set of carers with different habits and rules for another chunk of time. His fits would certainly be consistent with huge frustration and upset. And wetting himself could also be a sign of distress, although I must say that my 4 year old still wets himself at least once a week, whereas my daughter was dry at that age - children develop differently on that front.

I would tackle things head on because I think he probably needs openness and reassurance. DH or you should sit down and talk to SS and tell him that of course he doesn't have to call you Mom, he has a Mom and you know he loves her very much, but that you can have your own special relationship and he can have a different name for you, which can be your first name. Similarly with the Dad issue, he needs it explained that DH will always be his Dad and he will always be his son and Dad is the right name for him to use, because DH is very proud and happy to be SS's Dad. Try to talk to SS about how he feels, prompting him with questions like 'I guess it feel really funny living here for a while, does it sometimes make you mad that things are different to home?'. If SS is able to talk about how he feels it is the first step to making him less angry and more relaxed, and to establishing trust which can combat BM if she is attempting to manipulate SS against his father. Try to work out if there's patterns to his fits, are there triggers which set him off. Maybe you could come up with strategies for making him feel more at home, even simple things like having the same bedding and a similar routine. Maybe he also needs more contact with BM while he is resident with you? Those are some ideas, but basically in summary, he's 4, his lifestyle makes me feel stressed and I'm 40! The issues may be largely down to that and not to inherent problems with SS.