There's some heavy assuming going on about Morris and Munda. The truth is we don't know much about their relationship.
I don't know, I get the sense from "Leela's Homeworld" that the two of them are pretty devoted to one another; they lived so long with the shared pain of giving up their only daughter, and are willing to die
tentacle to preserve that secret. There's something powerful about that, I think, and it certainly makes their relationship feel real, devoted, loving.
Sure, we've seen Munda nag Morris a few times, but I don't think there's anything more sinister about their occasional annoyance with one another. The two of them seem to be like this mutant version of a usual Nagging Wife 'N' Henpecked Husband '50s sitcom couple. And, like, I guess you could say that breaking this couple up is a subversion of the sitcom cliche, and a kind of satire--but the way
it seems like they're doing it, just out of nowhere and seemingly with no regard for the characters' established relationship, is what makes me a little leery of the episode.
'Course, I'll have to reserve judgment until the episode actually airs; like I've already said, I'm a little worried about this episode, but also pretty excited to see what the writers do with the concept.