That's the main bullshit : he finds ntr everywhere, not because ntr is actually everywhere, but because anything like a love triangle, or secondary character having sex with someone the mc has no interest in, or the heroine is middle aged and NOT a virgin (imagine that...)... is rebranded as "ntr".
They're more obsessed about finding traces of ntr everywhere than me finding actual ntr lol.
And even then, like I wrote above, it's not ntr, because it's not meant to be constructed as such, it's pure drama that you can find in any work since fiction exists.
"WTF the mother of 2 isn't a virgin?! ntr!!!!"