The Origin of NTR
NTR is derived from the Japanese pronunciation of 「寝取られ」 (NETORARE), which directly translates to "being slept away" in Chinese. It generally refers to a situation where one partner in a romantic or marital relationship engages in a sexual affair with someone else, often referred to metaphorically as "wearing a green hat."
The Definition of NTR
The fundamental premise of NTR involves one of two lovers being seduced away, so there are two main conditions:
- The two are in love.
- One party engages in a sexual relationship with a third person.
With so many works available today, NTR has some ambiguous areas. For example, some consider an unrequited crush being seduced as a form of NTR, while others equate NTR with infidelity.
Let me share my thoughts on this. I believe that the appeal of NTR-themed works lies largely in the "inner struggle of the person being seduced". After being intimate with someone else, feelings of unease and sadness arise about their relationship with a partner, while they simultaneously experience pleasure with the new person. For an excellent NTR story, it should also elegantly capture the feelings of the betrayed, achieving this makes it a top-notch NTR piece.

Why is NTR so Popular?
I'm sure you've noticed on various adult video (AV) sites, especially on Japanese platforms selling R18 content, that NTR is always a popular tag. But why is this? Is it really that there are so many people with a "cuckold" kink?
Of course, under societal moral norms, NTR actually conflicts with our innate moral code. However, we can view such works and feel excitement without impacting ourselves—this is known as "a sense of taboo". However, I think the main reason for NTR's popularity is that when we search for storyline-based works, we rarely tag them as "pure love."
In the classification of narrative-driven works, NTR has dramatic plot twists and a strong sense of taboo, adding significant tension. Yet when we want to watch pure, sweet romance, without a "pure love" tag, NTR appears relatively popular by comparison.
Xiao Xue's Recommended NTR Works
H Animation – オトメドリ

Adapted from a manga of the same name, this story spans two episodes and features a male protagonist who receives a mysterious DVD. He discovers the content depicts his childhood friend, with whom he has a significant emotional bond, being violated by a group of unknown older men in a large room.
Watch Online Links:
hanime.tv: Watch H Animation Online
hanime1.me: Watch H Animation for Free
avbebe.com: Click to Watch H Animation
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H Manga – [灯色の研究室 (灯問)] NeuTRal Actor

Ryo Kazama's girlfriend, Kana Akizuki, is a rising star in the drama club. Though they should be a loving couple, Ryo's inferiority complex about their status difference leads to growing sexual disinterest, prompting him to suggest Kana put a green hat on him.
Reading up to this point, you might think this storyline is ridiculous, but in NTR works, if the characters are too smart, the plot doesn't progress. Please bear with it. (Side note: reality can often be stranger than fiction, and news stories frequently offer even more dramatic plots.)
Watch Online Links:
18comic: Watch H Manga Online
Gentleman Manga: Read H Manga for Free
nhentai: Click to Read H Manga
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AV – ABW-087 ※ Disturbing NTR’s Worst Scenes: The Girl I Promised Happiness Was Taken and Broken by an Old Man. Remu Suzumori

Remu Suzumori celebrates the first anniversary of her relationship with her boyfriend as she becomes a full-time employee at a convenience store. However, on her first day, she is caught stealing by a colleague, Kubota, and subsequently blackmailed.
Although the reason behind the theft isn't mentioned in the film, it does clearly narrate the backstory of the despicable Kubota, a rather unique filming approach. The ending even includes some bloopers to slightly alleviate the discomfort brought by NTR, making it highly recommended.
Watch Online Links:
Jable: Watch AV Online
GGJAV: Watch AV for Free
avbebe.com: Click to Watch AV
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NTR content is actually harder to portray in AV as they tend to be too long and detailed, and only a minority truly watch for the plot, whereas animes and mangas can portray the tension of NTR in a concise way. So those interested in NTR works are more recommended to seek them out in anime and manga.
However, it's important to remember that the storyline is always just a fiction, so never harm those around you simply because you wish to imitate these works~