— A Crossing Man and Woman reader, summing it up perfectly.
Netorare (寝取られ, lit. "cuckold", also commonly abbreviated as NTR) is a notoriously controversial genre of Hentai (or, in rarer cases, Ecchi), with a degree of infamy perhaps rivaled only by full-blown Guro.
Typically, a heroine will be introduced as having a significant other, which may be a husband, a boyfriend, or even a partner in a BST affair. The story will then show the aforementioned heroine being intimate with another man (another girl just doesn't pack the same punch), thus provoking jealousy in the audience by proxy. The nature of the affair varies, and the parties involved may be willing or unwilling. Sometimes the girl is simply cheating, sometimes it's in the form of the Scarpia Ultimatum, sometimes or the man may simply be pimping his sweetheart out to earn their bread. As you may expect, this is on the bad side of Good Adultery, Bad Adultery.
See also Adult Fear, Defiled Forever, I Have You Now, My Pretty, Please, I Will Do Anything!, Sacred First Kiss, Scarpia Ultimatum, and Your Cheating Heart. Very often features an Idiot Plot, and is perhaps one of the few non-comedic techniques which may execute it to good effect. The reverse of netorare is netori, cuckolding someone else's love.
Hen Zemi: Komugi harbors this particular fetish,and actively tries to invoke it with his girlfriend.
If a shoujo or josei manga has a Bastard Boyfriend as a male lead, it'll have at least a NTR variation in the plot. I.e., the infamousSensual Phrase scene in which Sakuya snaps on Aine, drags her home by force and barely stops himself from raping her comes from a misunderstanding in which Aine was unwillingly given a hickey by a Hopeless Suitor and Sakuya thought otherwise. And Haou Airen has Hakuron raping his girlfriend Kurumi in front of her newfound friend Kaafai when she leaves him, to force them see that Kurumi is with him and only him, as well as Kurumi having Sex for Solace with Hakuron's Dragon Fuuron despite being still with Hakuron, and Reilan trying to get Kurumi gang raped in front of Hakuron specifically to taint her in the eyes of everyone. (Two of the three HA examples, however, backfire HORRIBLY) .
Nozoki Ana: A very huge, hurtful example that many readers were predicting for ages. Not only was Yuri Kotobuki, the girl in this situation, cheating on weekends, but she decided she'd rather have sex with her rich boyfriend instead of spend Saturday with her other boyfriend, the lead male Kido. On Kido's own birthday.
Alluded to in Air Gear, with Hako referring to Ringo as "NTR # 1" and accusing her of cockblocking either her or Kururu, as they both squabble to become Ikki's link turner. Ikki chooses Ringo anyway.
While there's no 100% direct netorare in Mawaru-Penguindrum, the extremely complicated Love Dodecahedron that included almost all of the cast gave place to the following Memetic Mutation: "(insert name) is getting NTR'd". It actually started as "Kanba is getting NTR'd", due to Kanba Takakura showing open jealousy towards his little sisterHimari's closeness to her handsome new doctor, Sanetoshi Watase; the subtle and not-so subtle parallels to the Netorare Genre were inmediately oticed by the fandom, and one thing led to another...
Similarly, the Fate Zero fans refer to Kayneth, his fiancée Sola-Ui and Diarmuid!Lancer (whom Sola-Ui falls for) as "Team NTR". This isn't exactly an example: Diarmuid had no romantic interest in Sola and she probably never cared for Kayneth to begin with, as their engagement was an arranged one and she was not happy with it. Kayneth certainly felt NTR'ed though.
A minor meme in Bleach refers to Tsukishima's powers to brainwash and manipulate people into loving and caring for him as " Tsukishimawill get you NTR'd".
There are many PG-13-rated parallels to the Netorare Genre in the plot of the Ah! My Goddess movie. More exactly, the Anti-VillainBig Bad, Celestine, sends out his right hand and local Dark Magical Girl Morgan to ensnare Keiichi's attentions and try driving him away from a amnesiac Belldandy. Since Belldandy had retained some of her feelings for him despite having been mindwiped... when she saw Morgan plant a Forceful Kiss on Keiichi and mistakenly believed that they were lovers, her mind collapsed completely... and Celestine used her jealousy to get to her and turn her into his Apocalypse Maiden.
A large portion of H-Doujin of Ah! My Goddess are NTR. So much that they make multi-volumes from differant artists. And with the revealed that Heaven surpress Keichi's urges towards Belldandy and her knowing all about it, all of those doujinshi take an interesting twist.
In Black Lagoon during El Baile De La Muerte, there was one such scene between Roberta and a former colleague during her assassin years, and Garcia Lovelace is watching close by. Soon after that Roberta kills the guy and almost kills Garcia after he reveals his position as she is far from sane at the moment.
In Berserk, the first thing the newly transformed Griffith-turned-Femto does as a Godhand is to rape Caska right in front of Guts, who is Forced To Watch. Guts can't do anything but cry at the horrific sight as an Apostle pins him down, gouging out his eye in the process. Made even worse with Caska's last words before losing her sanity: "Don't watch..."
Fan Fic
In PITCH, Light has sex with L and, after tying him up and gagging him, forces Aiber to watch. It's different in that L and Light are already together, and Light is trying to make Aiber realize that L is not available.
Speculated by some to be one of the reasons why Prussia tortured and raped Hungary in front of her love interest Austria in the infamous All He Ever Wanted.
Defied in Reconciliation, a Katawa Shoujo fanfic in which Lilly and Hisao get together after Hanako's bad ending and Hanako, despite having isolated herself from the two out of guilt, harbors feelings for Hisao. Word Of God states early on that the fic is not intended to be NTR, and in the third chapter, Lilly calls Hanako to tell her about Hisao's death.
Film
Indecent Proposal, in which a millionaire (Robert Redford) offers a young and broke couple (Woody Harrelson and Demi Moore) a million dollars in exchange for a single night with the very attractive wife.
Literature
In Paul Di Filippo's short story And the Dish Ran Away With the Spoon, the heroine is stolen by an intelligent assembly of household objects, including a vacuum cleaner, a food processor, and a blanket. That hurts.
Music
The Irish ballad Seven Drunken Nights is sung from the perspective of a man whose wife is cheating on him.
Jairo, "Para verte feliz" ("To see you happy"). It's sung from the POV of a guy who knows his beautiful girlfriend's old flame is coming to town and chooses to rather have them almost tongue-kissing in front of him rather than confronting and then losing her, since he's that much of a Love Martyr towards her.
Ancient Bloodlines speaks of a vampiric Babylonian priestess' lesbian lover being taken from her forcibly by the En emperor. Turns out the lover eventually fell for her abductor in typical NTR fashion. Unlike other netorare stories, the priestess got her revenge on them by creating the Iltani and edimmu.
Diablerie causes vampires to sometimes pickup traits of the soul they ate. It's implied that's why the couple do what they do, despite their actions mirroring their own tragic histories.
Mess with their heads. Get it so the victims love their keepers, will do anything for them (even better if they can work one of the couple against the other—so sweet, that betrayal).
Tends to happen quite often in The Sims, especially if you're not careful with relationship management and/or don't have a No Jealousy hack installed and decide to have a threesome or Love Dodecahedron.
In Grand Theft Auto IV, Vlad reveals after a mission that he has been sleeping with Mallory, the girlfriend of Niko's cousin Roman. When Roman finds out, he is understandably distraught, leading Niko to chase down and kill Vlad. Weirdly, this actually results in something of a happy ending, as Roman lies to Mallory and says he did it and she is impressed and touched and even a little turned on, and their relationship improves, culminating in a wedding. Of course, your choice for the penultimate mission can lead to Roman getting killed, but...
