I also have this issue. I have a large home with 4 bedrooms. There 3 couples living in this household. I designed bedrooms for each couple, with beds for each couple. When I use the Whoohoo interaction (either through chat or clicking the bed directly) they always use the same bed. They will not use any other beds in the house. The bedroom they "prefer" is on the main floor. If someone is sleeping in it, than the others can not whoohoo at all. They begin the interaction by aking their partner, but the then the interaction disappears. I have tried moving, replacing the beds, removing the problem bed, using a different family, and making sure nothing is placed around the beds. Results are always the same. Even with the new family, they still had a "prefered" bed.
*I do not have any CC in game
*I have the DVD Premium version of the game
*I had this problem before the last two updates (since release)
*I am a laptop player (Hp with Windows 8)