Why won't my family move to a new house?

You can't always tell if your spouse is moving to a house or not. Try travelling to the house you want you and your spouse to move in and he or she'll be there. If this still happens, try to wait a few days or reload and saves very often.

This happened to me, it resolved itself over a span of a few ingame days. I simply didn't go to the manor for a few days. I stayed out questing or slept in inns, and when I returned they were at the manor.

Do you have a chest and bed for the kids in the new house? You have to ask both the wife and the kids to move, and must have a bed and chest for the children in the new house before the option to talk to them will appear.