Nah, you're talking about cuckold; the difference between cuckold and NTR is that cuckold is from the perspective of the man, and NTR is from the perspective of the woman. Obviously for cuckold to work the man has to find out, but that's not necessarily the case for NTR; some NTR stories just focus on the woman's feelings of guilt about cheating become feelings of pleasure, and don't cover the guy finding out about it at all.
Cheating and NTR are similar, but the difference between them is that NTR has to initially have some sort of coercion; the woman doesn't initially want to have sex, but she feels she has to. The cheating genre doesn't necessarily have that aspect.
Your literally wrong on all aspects. First off cuckholding is when the man is aware of the sexual relationships going on with his significant other. NTR is when the man isnt aware or when he does become aware he is sad/angry/jealous.
Cucks are fine with being cheated on, NTR'ed males dont like being cheated on.
The main character of this game is a Girl, you play as a girl. Girl main characters are the ones doing the cheating in these types of games, she is cheating......she is being corrupted. Thats why these types of games are tagged "cheating" or "corruption" because the girl becomes a slut.
For this game to have a NTR tag the main character would need to be a man and we would play as the man and watch as our Girlfriend becomes a slut or gets sexual with other people without our consent, thats NTR. If she does have our consent THEN is becomes cuckholding. Nice try guy but I am a master of this topic being only able to enjoy NTR hentai and Corruption Porn Games like Katie's Corruption, Angelicas Temptation, GGGB, I can go on but you should get the point.