For some reason exhentai links dont work for me
You can try te e-hentai link instead.
https://e-hentai.org/g/1289478/7b660c61a2/
I think i know the WN version of that one, or a similar 1 sinc ei think the princess in that case was just cursed plus the relationship was more than platonic i think.
Anyway reading the comments gave an idea for a novel or even game, basically a story like that where the heroine needs to fuck around for power, it could a be a curse or the power itself is like that but here is the catch: is not the sex itself but the sense of inmorality and corruption that gives her the power, like she knows is bad but the mor evil (because cheating is bad) the more power she gets and the more she does it the more evil she herself becomes, sort of a story of power corrupts.
Yeah, I just started reading that novel after seeing the illustrations for the light novel on ntrblog. You guys can find it here if you're interested.
https://novel18.syosetu.com/n8395ed/
I didn't think I'd like it since it centred around the heroine with very little of the knight PoV and I prefer the NTRed guy PoV, preferably with mystery. Plus she's got a curse and I usually hate anything like aphrodisiac drugs, magic, hypnosis or brainwashing in my netorare. But this was a lot better than I expected. The sex scenes are hot and while the princess believes that the curse mark is making her feel the urge to do immoral and promiscuous things, it's implied even early on that all it's really doing is activating whenever she gets aroused to stimulate her sexual desire to the peak. It's not creating the feelings from nothing, it's just helping her get really horny so she wants to do something about it. She still knows what she's doing, she's still in control of her actions, she knows she could easily stop whatever is going on, she just doesn't really want to. She's just giving in to temptation and anything she says or does when she's in that mood comes completely from her. Once you realise that it gets really hot. The fun part is seeing her tell herself she's not going to do it, firm her resolve, only to waver when she encounters the opportunity to indulge her desire, slowly falling deeper and deeper.
Trust me, it's a lot better than you'd expect.
That novel is actually already pretty close to the situation you described, but i like the way it happens in the novel better. The fact that she guesses that the mark is making her magic stronger as she indulges in lust does give her another excuse to give in to temptation, but since she also thinks it's causing her desires, she believes her desire to sink into immorality and corruption comes from the mark, without realising it's her own feelings. So insidiously it becomes a justification, that it's not her fault, that it's the Mark
making her do it. If she knew it was her own feelings the shame and self-loathing might let her resist it better, but since it's "not her fault", then it seems excusable for her to give in, since she has something else to blame. And the more she does it, the more she gets corrupted. I'm only at the eighth chapter right now, but i'm loving the way it's going.
I really like situations where the heroine in netorare seems pure and faithful and even after she betrays her partner she continues to act that way, while showing her lewd and ecstatic face that her partner has never see to the other guy. Finding out that she was able to smile and act normal in front of the protag with hardly any suspicious behaviour, while wildly betraying him with another man, really gets my motor running. It also hits me harder when she's still clearly the same person the protag fell in love with without any radical personality changes, yet that same girl still chose to betray him and was even able to deceive him about it, lying to his face with a smile. Feels much more harder hitting to me than when she becomes like a completely different person, to the point that it feels more like the other guy brainwashed her, rather than seduced her.
When the heroine has a very clear an noticable change, like in the early jinsei NTR games, while I can understand how it appeals to many, it just doesn't do it as much for me. Not that there shouldn't be signs, but I like it subtle. Things a man can easily let pass without being suspicious, like a small change to her hairstyle and usual clothing (to one the other guy prefers) and small changes to her habits and hours when she'll be away from home. Stuff that'll immediately set alarm bells off for the readers, but not necessarily for the guy in question.
Just my taste.