Funny thing is I been recently branching out looking for NTR / sharing games just for something different since nothing is a turn off for me as im pretty open minded. My first true NTR / sharing game actually had a good story. While yes the game would be good even without that kink in it. But the way it introduced those themes actually made the game enjoyable wasn't just jumping from lewd scene to lewd to shoe horn that kink.
Unlike the other game ive tried with the same concept tho the second game I tried was enjoyable just because they made fun scenarios' or the wife was fun tho was just lewd scene to lewd scene and no real story. So I totally see what you mean by uninteresting or stupid characters cause tbh the second game I tried not one character was interesting. If wasn't for the wife or scenario's just being fun to read would of dropped it so fast.
I think my favorite kind of games are those that include what would be described as somewhat ntrish scenes, but not explicitly about a "Stealing a girlfriend" fetish - more just that it's an open ended world, where indeed other people have sex, but not always in a malicious context. Just like the real world, there will be other npcs with bad intentions, and other npcs with good intentions. Examples would be like Runaway Princess or many of the LoP games.
Without this element, stories tend to get boring fast and everything blends together in a giant pool of "blah blah blah you're a young man, perhaps with a family blah blah blah there's a group of women around you blah blah" like I already know how this story goes, for the 1000th time.
Unpopular opinion amongst the F95 crowd: Everything related to anime sucks. I hate the art style, I hate the tropes, I hate the censoring, I hate the stories, I hate the writing. It's sexuality viewed through a 12 year old boy's eyes, and I'm shocked it represents at least a quarter of games here.