Goddessdammit. I thought if Momo was as weird as Mizuki and Yanagi, we'd have seen it at the start. So I let my doubts sleep since that was five chapters with anything on the radar. Only for the reveal to blindside me !
Of course, a NTR fetish. I mean, at this point, why not ?
... Huh, if Mizuki starts dating Yanagi, would Momo become interested in her ?