I have a friend from 'Minican who told me the story of the cuckoo bird, whose habits lend its name to the word "cuckold." He is of the belief of cuckoldry to be the purest and highest form of sexual arousal. He also believes the real and true sexual bond is between the bull and the cuckoo bird, so to speak.
I dunno, NTR for Netori isn't bad imo. It just should be labelled as such in addition. It's bad when the NTR tag gets slapped on anything involving non-MC sex because some people can't stand not always being the centre of attention.