For what it's worth, I have always considered this to be atleast partially (depending on the route) an NTR story, as I've stated very early in the thread. Classic NTR hentai by authors like Sanbun Kyoden, Arakure, Itou Eight, Ichimatsu or Tamagou, among others, were a major influence on the writing. But somehow, despite some of these authors pretty much being the cornerstones of the genre, that classic, female MC centric NTR is not considered NTR in the realm of western erotic games.
Not that I particulary care anymore (god knows that I don't want to partake in yet another "what even is NTR" argument), just wanted to get that out: I , the author, think its NTR, but by the site's definition, it's not.