Have you tried resetting them?
- open cheat console (shift, ctrl, c)
- type in: resetSim *
- hit enter
That should reset everyone.
Also, when that happened to me what I did was actively move out of the household. So, basically:
- go to edit town
- instead of clicking on the household you want to go to and choosing "switch household" simply go to the button at the bottom (where the library and everything is found) and choose "change active household"
- select the one you want
If that does not help, try a factory reset: http://answers.ea.com/t5/The-Sims-3/FAQ-Troubleshooting-Steps/td-p/714
