So it seems you really haven't understood the NTR-part.
What you described is a typical "I-am-the-hero-and get-them-all porn game" and that is for sure NOT what most NTR-Fans want to have...
I personally don't like these "your girl will get stolen nomatter what you do" games, and yes most ntr-games could need a lot more story...but when you switch from a guy who suffers from the fact that his "love of life"/soulmate/etc is taken from him to now I gonna take all the ladys, it isn't really believable, because most of the Male Protags you play are sensitive, are not "strong" and mostly somehow naive/dumb...and suddenly you want him to be superman...
I would recommend ntrmaster stories on literotica (reunited especially) to see what most want to have in ntr...pure suffering.
I would like to see more ntr with options to avoid it (not just switch for on/off) or winning her back...
That would be need some good writing, but could be satisfying too, but most dev's seem to believe the only way to get ntred is: no choice she will be gone OR you have to be an asshole to her, and she will be ntred... I miss these "bad guy (which shouldn't be all the time fat ugly/stunning & having a big package) who will seduce her over time.
So far, enjoy life as long as it goes...
I think I get it for the most part, granted, I don't enjoy it on any sexual or kink level, but I do understand the use of it for emotional immersion in plot. The example I gave is just 1 condensed hypothetical that I came up with off the top of my head & even that can make for a good story or a good game depending on, like you said, how it's written. There's other ways it could go too. Maybe instead the protag goes on a mutually destructive revenge path that destroys the wife, her lover & himself in the process, or maybe in the "wealth acquisition" stage of the game, if he doesn't play it right, he goes bust & is the one left with nothing, etc... So I'm not as much suggesting replacing the "cuck gets cucked & is sad, the end" cookie cutter garbage with "Protag is uber male & wins at everything, the end" garbage either.
What I'm saying is throw the cookie cutter out completely. get rid of the paint by numbers template & instead weave these themes into a unique creation.
I mean some good examples of the opposite, (though not in the sexual or hentai realm), is the classic book Flowers for Algernon. In that story we see a mentally challenged, but happy man undergo a test for a neurological procedure, alongside a mouse named Algernon. As a result he becomes not only normal, but brilliant both intellectually & socially, & as a result of his meteoric rise from ineptitude to genius, he first finds happiness, love, begins accumulating wealth, but then that descends into alienation, depression, angst, as his neurological development propelled him beyond his peers, rendering them essentially his mentally challenged counterparts by comparison. At this crescendo in the story, (as Algernon's development paralleled protag's), Algernon's neurological function rapidly reverted back to that of a normal mouse & then died. In following, Protag's mental state rapidly reverted back to his original state of developmental deficit, but he also returned to being happy in that mentally challenged state. In this we see the complete opposite of the story arc. Protag starts feeble minded, weak, alone & with nothing, then science, & he gets love, wealth, social status, etc... Finds it brings him misery instead of happiness, then the science ends up being temporary & he reverts back to his original state. Even with the protag not getting everything in the end, It's still a DAMN GOOD story. Still to this day one of my favorites. & that's because it was well written & in a lot of ways threw the cookie cutters out the window & got creative.
Another good example of, well not good writing because sadly it is reality instead of a work of fiction, but very much in the vein of the NTR theme is the tragic story of Jason & Brandi Worley. They were married with kids, then one day Brandi starts cheating on Jason with the Neighbor. Jason confronted them on it & threatened divorce. However, Brandi blackmailed him not to, threatening that he would never see his kids again if he did & saying she would use a suicide attempt on his part from when he was still in high school as leverage in court to make him appear unfit as a parent. A year or so later, he turned to Reddit to seek advice on what to do, (Google u/jasoninhell & u/jasonincode), since she started cheating again. After numerous responders encouraged him to divorce her, since she has no case to keep him from his kids, he finally decided to do so. However after he served her with divorce papers, while he was sleeping, she killed their kids & attempted to kill herself. After her failed suicide attempt she turned herself in & now will spend the rest of her life in prison.
Now, since that example was actual reality, obviously it is gut wrenching & absolutely should never have happened. As a father myself, I can't even imagine what I'd do if that happened to me. Only thing I do know is that if my wife did that, (the killing my kids part obviously), I'd be the one going to prison instead of her because I'd kill her. Not a question in my mind about that.
However, if we remove the reality component of it & look at it as though it were a written work of fiction, that would make for a hell of a compelling story. & it would make for a story that would appeal to NTR fans, (for the NTR content & the protag losing in the end), & the non NTR fans whom just like a good story that kicks you in the feels.
Other great examples are the work of Freebird Games. Ken Gao has created unrivaled masterpieces with To the Moon & Finding Paradise. If you're not already familiar with those 2 games, you are unknowingly depriving yourself of objectively the 2 greatest things to ever be created in RPGM or in the indie game industry period. & that is because they are amazing, immersive & engaging stories that resonate with the observer of them.
Now sure, the games here are not the examples I gave. They are game form porn to give horny guys something to nut to. I get that. I'm just saying that just because these aren't a grand emotional roller coaster epic like Finding Paradise doesn't mean they have to be "cuck gets cucked & is sad" wash, rinse repeat. Some degree of that level of creativity could make these games much much better too.
As for my example not being realistic, Sure I'll grant that. But like I said, it was a condensed concept squeezed down into a couple of paragraphs. That's why HOW it is written is so crucial. If it's fleshed out right, given the space & time for the details to actually take form, it COULD be very realistic & compelling. The framework is in the story boards, the Story is in the writing.
Meanwhile, even if we look at some of the contemporary NTR writing out there, such as that Theresa Simpson thing by Feuege, (or whatever his name is), THAT is an abomination from a literary perspective. It is so beyond irrational & unrealistic that it's borderline unreadable. & with the "cuck is cucked, gives up & is sad" stuff, All I find myself wondering is "where the fuck is your backbone?" I mean sure they are usually weak, but hell. Most people in that situation would either walk away from it all or would self immolate & go down fighting. I know I would. If I were in the protag's shoes, Even if I knew for a fact that fighting back would be futile & I'd lose, at least I'd go down kicking in their teeth as much as I can. But again, that comes from poor writing.
Anyways, that's just my thoughts. I appreciate your input though too.