I don't know if anybody else saw this posted over on another website, but this study done shows some pretty interesting results on infidelity in Japan:
https://sp.comics.mecha.cc/mechamaga/articles/b-uwaki-nr
Almost 1/3 of japanese women have admitted to cheating although its about the same for men (a little higher but not much)
What I found really interesting was 2 points however, one what defines cheating (eating with somebody else for example?!) or physical contact (my friends who are "huggers" are apparently sluts by japanese standards). 1/3 however only considered intercourse/oral to be the point of where infidelity occurs...this certainly reflects how Japanese are really reserved in social interactions outside of their 'close circle" and where that line of intimacy crosses due to culture norms outside of it. Regardless it makes me think just how powerful the act of intercourse is as NTR as the most extreme act of infidelity in japanese culture...well except for about 2-4%
who don't consider sex cheating lol....ooooook.
The second point of interest in regards to NTR and this study was when women said they cheated because they were going with the flow (19% of the time) when somebody hit on them lol...geez better lock up your anime waifus at home!
Although compared to say the UK where I've read studies that have said 46-52% of women have cheated on their partners...well Japanese women are still rather conservative when it compared...