I play 100households spread all over, of course it goes slowly for each of them, but at least I get lots of variety. Eventually two households merge as kids marry, or I get a new EP and am urged to create a handful more households ...
If you never played multiple houses on rotation, perhaps it's time to try it? Create 4 families, send them to different worlds, make them meet often, build relations and join the same clubs and events etc. Give them different careers and preferences, for more variety. You could make them based on 4 siblings, making them related, but then it would be harder finding love stories and new couples.
I never had your problem, LOL :) I never create a household without having tons of plans for them, and I know where the only vacant lot in my game is :)
