Thanks to everyone for their suggestions. I wasn't just clicking on the bed - whenever I clicked through the romance options, it wasn't listed there, either. Seriously it's like impossible to woohoo with this guy.
But I guess since she is able to woohoo with other sims, the problem just lies within him for some reason. I'm kinda bummed but more just curious as to why. It's not a lot issue because the other sims she's been successful with have been on this lot, in the same bed that isnt giving me the option with the other guy.