There's two mentions in Gaiden V. 1-- one when they get into the fight and Kenren says, 'if someone insults me, they're insulting you'-- I think meaning because Tenpou's technically working for him-- and Tenpou's all coy and cute about it, and then Nataku's father (oh, I hate him) does the whole submissive/wife thing with Tenpou and Tenpou hits him, like, really hard.

And yeah. Sex or no, married. Love them.