I recently realized that I don't like it when a character who's getting cucked are deserved it. I got a reaction along the lines of, “umm, well okay. That makes sense. You got what you deserve.” The prose of life. A far greater emotional response is when a character absolutely doesn't deserve it, does everything right and...makes just one mistake that leads everything to a downfall or doesn't make that mistake at all, but still comes to suffer. You, guys, know what I mean, right? It's just spice things up.
Yea, your name adds up to your tastes.
Jk, but yeah, it does hit harder when it's undeserved. The ntr games that stuck with me the most were the ones where the MC (or the girl) are just victims of circumstances or extreme naivety - and get their lives/dignity/relationship ruined by people or things way bigger than them.
When I play games with "deserved" cheating it usually just feels like comeuppance. Fucking a housewife in one of these random harem games, which is mistreated or stuck in a shitty situation by her shitty husband - that doesn't really do much bc the guy is portrayed as a piece of shit. It actually feels like it's only fair for the ntr to happen. IMO it doesn't take away from the enjoyment of it - but of course it's gonna hurt more if the story is darker, and some people really get off on the suffering, pain of loss and "corruption"/loss of purity aspects.
An example that works to explain this for me is Hero Party Must Fall. For some reason I hated Erin from the start - so seeing him suffer as a victim of Mars' shenanigans was no big deal for me - Cecille giving in to him step by step from the girl she starts the game as was incredibly hot. In fact, I felt more simpathy/empathy for the girls than I felt for Erin's dumb ass. The game's still really good - but I didn't care about Erin at all, so there was no "pain" in it.
I guess it's all a matter of taste. NTR comes in many forms and people enjoy it in different ways (lighter or heavier stories, playing the "stealer", playing the girl(s), playing the cuck, watching the story unfold as a spectator, etc).