You are missing the point of NTR. This is not Netorase, they turning their hearts against Harry is the sexiest form of corruption. It's him who still has to love them. Not the girls, they have to despise him.
Point of NTR is Jealousy.
Just like the point of Romance is Love, the point of Horror is Fear, the point of Action is Hype.
One single emotion.
...Or a group of emotions, if you want to be nitpicky about it.
If a girl despising the man while cheating on him makes you MORE jealous - then that's what matters.
Don't let anyone take that away from you. You are here for that emotion and you've got it.
I'm feeling the exact opposite.
And I'm just trying to explain why I feel that way. While 'maybe' uncovering some useful rules about human emotions and storytelling.
1) "The girl despises her boyfriend and BECAUSE of it she cheats on him."
2) "The girl just cheats on her boyfriend."
3) "The girl loves her boyfriend to the death, but DESPITE it she can't stop cumming while cheating."
1) No contrast.
I have no idea what she even feeling during sex. Is it good? Is it bad? Is it just a normal sex? Or her craving's on the level of craving for a cake in the early morning?
I don't know.
There's no contrast. There's nothing to compare to - because she's losing nothing with this cheating.
Imagine if when Romeo met Juliette their families were best buddies.
Would that make a better story? What would you be able to tell about their love? Is it as scorching as the sun or is it just another one of these ball meets? Will they love each other for the rest of their lives or will they get bored in a week?
Who knows. I sure don't.
2) Weak contrast.
It's akin to incest: "I kinda shouldn't, but I kinda want to."
it makes the feeling a bit stronger, but generally good stories will add something on top of that. Though it's still an easy way to spice things up a bit. And it is working.
Hence both cheating and incest are quite numerous - but the ones that stand out are the stories that throwing something more into the mix.
3) Strong contrast.
If the girl sacrifices cake to get a cookie - it means her craving for the cookie is at least a bit stronger than her feelings for the cake.
Cookie>Cake.
So the stronger her feelings for the cake we make - the stronger we can feel her craving for the cookie.
If Cake=10, then Cookie>=11.
If we'll be able to show that Cake=1000, then Cookie is at least a 1001.
The cheating sex feels BETTER the more she loves her boyfriend. (for the reader)
Now.
If the girl sucks a cock DESPITE her love - that means her craving for this cock is AT LEAST a bit stronger then that love.
But if she sucks a cock BECAUSE she doesn't have that love no more - erm, then what? She's just a woman who sucks a cock.
What you want me to feel about her?
...And she's having a shitty attitude by 'despising' her boyfriend on top of that - but that doesn't really matter. We're here not for moral-policing.
It's just if there's nothing else to feel about her - she's "just a woman who sucks cock" - then that's the only thing left for me to feel about her.
Shitty.
Again, Laura's foundation is incredible. If it wasn't I wouldn't be here writing this wall of text. It's just her character development is worse then it was at the start.
And it should be the other way around.
You don't put work to feel less.