A 'Good ending' is an ending that completely bypasses or, at the very least, interrupts the NTR.
All NTR game have this very early in the Game.
A 'Cathartic ending' is one in which, after the NTR has fully run its course and the FMC has effectively become an antagonist to the MC, the guilty parties are shown to face consequences.
That doesn't mean the MC and the FMC have to reconcile and live happily ever after. I doesn't even mean the MC has to be happy at all in the end. Just an ending that demonstrates that age old truth:
"You reap what you sow..."
Yep, that's what I am talking about. APBLU has this kind of ending in both Hero path. Normal path where it shows Laura's realization, guilt and concern and Alt path Where Luca is stuck in a loop with MC, he don't want to build a harem or get a wife or GF just want to cuckold Harry so he don't have any loved ones (I always wondered if Harry became g*y at some point will Luca also becomes one
). Most NTRs don't have this Cathartic ending.
But, as I've said before, you're more likely to get that kind of ending from Japanese NTR game devs rather than western ones who subscribe more to the westernized cuck fetish.
Yeah most Great, Good Corruption/NTR games are from Japanese and sadly in RPGM. In My Blue Collar Girlfriend both endings show the characters are all became twisted by the experience and one implied none of them is happy and the other implied they are somewhat accepted their twistedness and trying to be happy.
I could see Sophie ending up like the woman in that book you referenced on any ending where her and Zack don't end up together long term, and I suspect it'd be the natural progression even if they did end up together long term. He's not a one woman kind of guy and I really don't see him not getting tired of her at some point.
I don't know why but most NTR games makes the bull a one women guy specially for the FMC in the end. If that's the case then atleast show a afterstory ending like in the NTR Homestay.
I mean Shophie's current kink is cheating and thinking & shouting humiliating things about Felix, plus exhibitionism. So if she ends up with Zack shouldn't it be good/great/funny ending where she started to cheat on him with a old man with a very small penis?