Basically just looking for a longer form NTR manga (so there's more build up and emotional investment when she cheats) where the girl doesn't get coerced into cheating or raped, but actually visibly enjoys manipulating her boyfriend and humiliating him by making him watch her.

I'm sick of all this NTR where the girls cheat with some ugly ass old dude like hell that just takes me out of it. Let's be real, she'd want studs.

Bonus points if she seems or maybe even is innocent and sweet at first and her sadistic side develops with frustration at her boyfriend, but she keeps him around as her official boyfriend because getting off on the cheating is better than getting a new guy.

Bonus bonus points if he's not into it at the start but her manipulation slowly makes him a cuck.