"Three is a crowd for romance..." pop up...What does it mean?

I don't know, just another glitch I guess. It's never happened to me while they were sleeping or something. Although sometimes it does happen when, say, the parents take the kids to the park, and the parents aren't even flirting with each other but for some reason the game thinks they are and asks to break up the group and make it a date between the two. -.-