New Sims don't automatically move into households

When Sims get married, you are always prompted to choose where/how they move in and some of their money transfers over, and the new Sim becomes part of your active Sims. Lately, though, when my Sim marries another, they do not become part of the active family and there is no prompt to move in. I have to use cheats to add them to the family. How do I fix this?