@flyingbonbon: Not exactly. Cheating is merely the first step in NTR, but is
not guaranteed to lead to it. I've seen more than a few hentai that involved cheating without involving NTR; usually it's because the cheating spouse (husband or wife) is the dominant partner in the cheating. NTR pretty much always involves the "outsider" morally corrupting the cheating spouse until they either willingly abandon the other spouse or they turn into living sex toys that offer no resistance whatsoever to anything the outsider does (and may not even remember their past life, having been mindbroken in the process). Which goes back to the etymology of NTR, i.e. the cheating spouse being "stolen" by someone from the other spouse.
@Kumakamikaze: You're assuming that Komi's dad isn't as much chad as Tadano is in this scenario. Maybe Shuuko wants
double the chad in her love life.