>>46218648My guess is that the guys self insert as the NTR-er, because they are unable to get a relationship via normal means. So they want to envision themselves as the homewrecker that takes some random chick as the prize.
As for the girls, who the fuck knows since there's some female artists that love it for some ungodly reason. Maybe they fantasize being the object of affection between two guys, or maybe it's some weird way that they can envision it as yaoi.