I think this is the only sensible response I've seen so far. The other responders seem to have a 2 line attention span.
To address the points I've quoted, I never said anything about hating the grandpa. He is despicable, but everyone already knows that. There's no need for me to mention it.
My dislike for NTR is from feeling sorry for the husband. The other commenters missed my point about how the player isn't told until hours later in gameplay.
This leads into my response into your second point: just because the MC isn't the one being cheated on, doesn't mean it suddenly doesn't matter. I commented on this game because the developer note (not the genre tag) is devoted almost entirely to emphasizing there's no ntr. A more apt analogy would be if a restaurant assured a customer that there would be no nuts in their meal, then used peanut oil to cook it.
Your analogy is not correct because the tags and genre considerations exist within a framework. The dev doesn't "inject" NTR through some blindspot (like injecting peanuts through the oil and causing the alergy) because the genre tags refer to the player/protagonist. The dev gives exposition through a tragic story and describes the life and feelings of a selfish and shortsighted man in an extraordinary situation, leaving some parts of his character open to interpretation.
One could easily interpret this exposition as him being so miserable that he didn't even consider the possibility the girl he loved was there by her own volition and not through some form of coercion/power dynamic. There are other ways to interpret this depending on how you connect the dots, and mine isn't necessarily the "correct" one, but it still speaks to his flaws.
I understand that you, personally, may feel so bad about the "husband" that it may evoke feelings of disgust for a game which promised no cheating, but you have to put things into perspective and understand that it's your personal bias and not a deception on the developer's part. If you ask 100 people about the "cheating" content of the game, they will not even understand what you are talking about.
Your post wasn't completely unreasonable since you mentioned that the cheating doesn't happen to MC, but the way you set it up, being a member for 4 years and feeling the need to mention the cheating in this game with your first post, makes you look like you are coming in strong and overdramatic. This combined with my previous point is a recipe for disaster.
To take things even further, there are 2 points where the game shows cheating. One is Leah's mother, and the other is the one you mentioned. In both situations it ended up not being cheating (or at least, the injured party didn't give a crap about it). One was a sleazy businessman down on his luck, who tried to get business favor by whoring out his wife (so they wife ended up getting back with the school sweatheart, which created other problems and showed us again how flawed she was), and the other was a delusion.
It's like the dev is actively trying to avoid it. But cheating is something that happens in the world, and it's very fair to be used as a vehicle for character development/exposition as long as it doesn't break the "convention" the dev made with his target audience.
The convention still holds strong as far as cheating is concerned and saying otherwise is being unreasonable at this point (not saying that you did, just reinforcing the point), for the reasons I explained in the first paragraph.
