Sims Won't Woohoo In Shower

I'm having an issue in the game where the option for woohooing in the shower is grayed out, saying that "You need a potential lover on the lot." although my sims are either in a relationship or even married. The relationship bar is pretty much maxed out in green and the sims do not have the hydrophohic trait. It also doesn't matter where I put the shower; the option for woohooing in the shower still stays grayed out with the same message. Help?