I feel like this
excellent thread on what is actually NTR (and how to properly tell a story about it) should be pinned and/or the default landing page for anyone who has complaints after reading chapter 3.
Still waiting to hear from the haters if a traditional romcom love triangle is even allowed under their anti-NTR regime
Ntr doesn't need the MC and the heroine to have a bond to be called that, it applies EVEN when only ONE side shows feelings for the other.
The term means "stealing", it doesn't matter what, if it's a wife, a girlfriend or a person the MC is showing interest into.
Learn your tags, regard.
Also, don't be fking disingenuous, you know the difference between a traditional romcom love triangle and this kind of vibes.
Or maybe not since you are regarded, so let me tell you.
If you are reading a shoujo and the 2nd male lead gets close to the female lead you don't call it ntr for the main male lead, since you are watching the POV of the female lead, so it's just reverse harem. It's a shoujo after all, it's expected the woman to have many pursuers.
If you are reading a shoujo and the main male lead gets seduced by another woman, it's ntr to the female lead. Since it's her story, her POV, and her "simp" that is being taken away form her by another woman.