And I don't like the idea that japan is special with cheating. It's not. Every source that brings up it is either anecdotal, misleading, or just wrong.
I don't like to go off-topic, but I think some people might find this interesting, or at least thought-provoking. this particular discussion depends on what we mean by "cheating", because the Japanese don't see it like that and that's the reason there are conflicting sources about the topic.
the language have two different words for what we consider cheating:
uwaki (浮気) and
furin (不倫). uwaki can be roughly translated to "mistake", something like a fling, a one-night stand that makes both sides uncomfortable to think about later, or something done while drunk. furin on the other hand, is a full-on affair. "adultery" and "betrayal", to be precise.
furin is frowned upon, as it should be. similar to anywhere around the world, the Japanese look down on people committing it and the one responsible for it can be sued by their spouse legally. when we say they don't approve of cheating, it's furin we talk about.
but uwaki is a sensitive, different topic. if you ever get the chance to travel to Japan, visit Kabukicho in Tokyo. you'll find tons of hostess clubs, soaplands and pink salons there. just ask the girls if they have partners, and lots of them will say yes. because working in a red-light district (and in fact, visiting it) isn't cheating in Japanese culture.
as long as romance doesn't get involved, it's not furin for them. and uwaki, while showing the weakness of character, is not considered a big deal.
thing is, a lot of time uwaki can lead to romance, and that line between "OK" and "not Ok" is what makes NTR sort of a popular topic there, because it's like playing with fire. "when it goes from a fling to full-on betrayal?" NTR fans around the world might like the domination/submission aspect, or have a thing for humiliation, but for the Japanese it's a lot about the transition from one to the other. that's why you see some Japanese eroge show the girl feeling guilty and shy at first (the way uwaki should feel), but then go full brutal slut (the way they describe furin to be), like a personality change.
so when I for example said NTR might have more of a female audience in Japan, I merely relied on how they view "cheating" as a whole. it's more acceptable there to have fantasies about fulfilling your desires without getting romantically involved. it's totally normal for Japanese women to fantasize more about this than let's say, European women.