In case of a divorce or inheritance who gets to keep the kids, the house? How does that work in polygamist societies?
I think it will be weird for kids in polygamist home, maybe he will get extra money from his step mother, or in otherwise he can be ignored by his dad since his mom is not favorite wife for his dad.
What if the real mom hates her kid and the step mom wants full custody after the divorce? I think there is a simple reason why polygamy never went mainstream and mostly stayed with tribe like societies...