He'd go out every night looking for himself... and on the way... he found Ruth, Gladys, Rosemary... and Irving. I guess you can say we broke up because of artistic differences. He saw himself as alive...and I saw him dead.
A common plot element in crime television dramas, although the murderers are less likely to be seen sympathetically in such stories.
Played with in a Star Trek: The Next Generation episode where the plot goes both ways - a male character sees himself cheated on, murders both parties, and commits suicide, then a female character goes through the exact same scenario and reacts the same way. In actuality, both characters were being caught up in the psychic playback of events that happened to someone else in the past. And that someone else was not presented as justified, but as disturbed.
Unpleasantly required as part of the Goblin newbie zone in World of Warcraft regardless of gender - you have a romantic partner, that romantic partner then leaves you for someone else, and you have to hunt them down and rip out their cheating heart.
Mind you, the one they've left you for is also trying to sell you into slavery, so it's a bit more understandable.
Woman kills Man
Three of the "Six Merry Murderesses of the Cook County Jail" from Chicago fall under this trope.
This trope is the entirety of the Oxygen Channels's Snapped. Most episodes covers a Real Life case of an abused and/or cheated-on woman who killed her husband (sometimes father). They try not to paint the women in a sympathetic light, but the show still has a "You go girl" kind of feel.
Sometimes the husband is a saint and the woman is simply tired of being married but doesn't want to go through a divorce, or wants his life insurance policy, or the woman was actually a sociopath. These episodes don't count, though - they're just plain ordinary murder and not relevant to this trope. Women do sometimes kill people for reasons other than "bad men".
This is the setup for the Roald Dahl short story "Lamb to the Slaughter", infamous for its extremely clever Twist Ending. Admittedly, it's stepped up a notch as the husband explains to his wife — who's pregnant with their first child — that he's going to leave her for reasons implied to be this trope, ending with "And I know it’s kind of a bad time to be telling you, but there simply wasn’t any other way. Of course I'll give you money and see you're looked after. But there needn't really be any fuss. I hope not, anyway. It wouldn't be very good for my job." You might be tempted to konk him too.
Lil Kim has killed at least 2 boyfriends in her songs.
Anna Russell's songs "Dripping With Gore" and "Two Time Man" are (mild) parodies of this trope as used in country music.
"If You Hadn't, But You Did" from the musical revue Two on the Aisle has a verse beginning in soap-opera-style bathos and ending with a gunshot. It then turns into an angry List Song running down the reasons for saying goodbye to her husband, most of them having names like Geraldine and Kate.
The School Days media series of games, anime and manga have this going on in some of the bad endings, when it's not Murder the Hypotenuse. The most infamous examples involve Makoto being stabbed by Sekai (in both the anime and one of the original game's bad endings), but it also includes Yuuki being beaten to death by Kotonoha in Cross Days.
Greek Mythology: A subversion occurred when it happened by accident to Heracles - Deianara thought the clothing dipped in Nessus's blood would win her back his love, but it ended up killing him instead.
In No Way to Treat a First Lady by Christopher Buckley, Elizabeth Tyler MacMann is indicted for murdering her husband, the President of the United States. The last night he was alive, she confronted him over his latest infidelity and left a mark on his forehead with a Paul Revere soup tureen. Subverted when the actual cause of the President's death is determined to be heart failure induced by an overdose of Viagra.
In Susan Dexter's The True Knight, the opening scene is when the queen, having killed the king who sent her away to bring out his mistress openly, now goes to kill his mistress and their daughter. (The daughter is only saved by a Baleful Polymorph.)
Man kills Woman
Garth Brooks's "Papa Loved Mama" is presented as comedy. This version is sympathetic to both the lonely, cheating mother and the cuckolded, murderous father:
Mama was a looker, lord how she shined
Papa was a good'n, but the jealous kind
Papa loved Mama
Mama loved men
Mama's in the graveyard
Papa's in the pen
The ambiguous ending of George Jones' "Radio Lover" can be interpreted as this, involving a cuckolded DJ husband who comes home to catch his wife in bed with another man, and then sings the song's chorus, "The last words they ever heard."
"The Cold, Hard Facts of Life," most famously by Porter Wagoner. Here, the cuckolded husband is a traveling businessman whose frequent trips away drive the wife to cheat. He finally finds out when he comes home unexpectedly, hoping to surprise his wife with wine and a romantic dinner... but at the liquor store, he runs into a man that — unknown to him — is sleeping with his wife. The ending is left clear: the main protagonist stabs his wife and her lover to death, and he's left to rot in a jail cell as he awaits trial.
"Blood Red and Goin' Down," a No. 1 country hit by Tanya Tucker in 1973. Then a winsome teenager, the lyrics of this murder ballad fit Tucker well as a young pre-teen, forced to tag along with her father, who is bloodthirstily angry at his wife after learning she had slept with another man (the latest in a line, as implied by the lyrics). Eventually, the man finds his wife, in the arms of another man, in a ramshackle tavern and carries out his brutal deed... but not before sending the daughter outside. However, unknown to the father, the girl watches the slaying.
"She Wore Red Dresses," an album cut and de facto title tune to Dwight Yoakam's 1989 album Buenas Noches from a Lonely Room. Yoakam takes the role of the cuckolded husband, who married a beautiful young woman purely for how sexually enticing she was while wearing red dresses. The lust eventually dies and she walks out on him; betrayed, the angered husband stalks his wife, tracking her down to a lonely hotel, where he finds her asleep in the arms of her lover. After summoning his courage and bitterly cursing his wife, he walks in, holds the gun to his wife's head... and fires before she knows what's going on. "She wore red dresses/but now she lay dead."
Ambiguously implied in "Laura (What's He Got That I Ain't Got)," a No. 1 country hit by one-hit wonder Leon Ashley in 1967 (and re-recorded many times, including by Kenny Rogers). The ambiguity comes at the end of the song's second verse, where the cuckolded husband — having snapped for not knowing why his wife has been unfaithful or what qualities her lover has that he might not — takes a gun and demands an immediate answer, "if there's time before I pull this trigger."
Subverted in The Shawshank Redemption: Andy's wife was cheating on him, and he goes to jail for her murder. He's innocent, though.
The rap song "Scandalous Hoes II", which ends with murdering the woman for cheating, presented as completely justified
Weirdly appears on Rome when Vorenus finds out his grandson is in fact his wife Niobe's son by another man. According to Roman custom at the time it was not only Vorenus' right to kill her for her infidelity, but it was also what honor demanded (and Vorenus is constantly shown to put Honor Before Reason). He grabs a knife but doesn't seem like he will be able to actually kill her, so she flings herself off a balcony and takes her own life as a final act of love.
In Oscar Wilde's "Ballad of Reading Gaol," this is the condemned prisoner's crime.
He did not wear his scarlet coat, For blood and wine are red, And blood and wine were on his hands When they found him with the dead, The poor dead woman whom he loved And murdered in her bed.
The third verse of Dr Dre and Eminem's "Guilty Conscience" has the two arguing as a man's conscience on whether or not to kill his cheating wife and her lover (Dre tries to talk him out of it, but Slim Shady is goading him to go ahead). They both agree to do it after Slim calls Dre out on his own past ("You gonna take advice from somebody who slapped Dee Barnes?").
Appears to be the case in Nick Cave & the Bad Seeds "We Came Along This Road". The song's lyrics start with "I left by the back door, with my wife's lover's smoking gun" and then describe the protagonist going on the run.
Richard Marx, "Hazard", maybe. The male character's accused of it, but the truth is intentionally ambiguous.
Played with in Reba McEntire's "The Night The Lights Went Out In Georgia". A man finds out that his wife's been the town bicycle while he's been gone, and goes to kill her and his friend who she was last cheating on him with. He gets arrested for it, and as the title suggests, gets the death penalty. Subversion: the husband didn't do it. His little sister got to the cheating wife and the friend first.
The end of the video for "Down Low" from R. Kelly featuring Ron Isley as Mr. Biggs. After the latter walks in on his wife cheating on him with the former, who was told to keep her company in Biggs' absence but not touch her, he has the former beaten by his bodyguards and left in the desert. Biggs' wife is found in intensive care, having also been beaten for her infidelity, by a wheelchair bound R. Kelly, who witnesses her succumb to her injuries.
Played for laughs in one of the in-game books in Daggerfall. A Dark Elf man returns home to find his wife cheating on him and murders her in a rage. When questioned at his trial why he murdered his wife instead of her lover, he replies "I thought it better to kill one woman than to kill a different man every night".
In Adam's Rib, a wife shoots her husband after finding another woman in his arms, but he survives. Her defense attorney, Amanda Bonner, gets the jury to excuse her actions under the Double Standard grounds that a man shooting at an unfaithful wife would not be judged so harshly.