I switched to a house that had story progression on, and discovered that my sim had a girlfriend. Which is not an unusual event for story progression, but I thought maybe I'd move the girlfriend in so they could adopt some kids. Called her up and found out my sim barely had a relationship with her! She knew none of her traits, and when she asked about her work, the woman was unemployed (which did not go down well with my ambitious sim). I'd been trying to hook this sim up with Thornton, and she kept refusing because of the girlfriend.
I don't really mind the spontaneous love interest in story mode, now that we can protect certain families from interference, but surely they should have to build a relationship as much as the families we play!