So your spouse cheated on you, and it resulted in a child. Ouch, that's rough. What can you do now? Despite it all, you still love your spouse, but at the same time, you've got a lot of hurt and anger about this.
Here's an idea: Take it out on the bastard child. Of course it's not their fault—they weren't even born until nine months after the infidelity—but they're the embodiment of the affair, and you're going to punish them for that. This way, you can distance your feeling about the betrayal from your love of your spouse. This is one of the major reasons for Bastard Angst, and may be how they turn into a Bastard Bastard.
Usually this trope crops in in medieval or medieval-ish works, where men are more or less allowed to have a bunch of bastards, and their wives just have to roll with it. It can be played many different ways, from bitchy and hypocritical, to unfair yet sympathetic, or as some mixture.
Related to Wicked Stepmother, but with one major difference: These people aren't stepparents. Stepmothers—whose stepchildren were born before she got with their father, and weren't the result of cheating—are generally expected to treat said stepchildren with basic decency, and perhaps even be motherly toward them. However, in this trope, these women are not socially considered stepmothers. These children are bastards, the result of their spouse (i.e can be either husband or wife)'s cheating. And this trope gets really ugly if the kid is also a Child by Rape.
Usually a female trope due to the classical Double Standard that women get in more trouble for adultery, but can apply to a man who's wife had a child from an affair with another man. Usually discovering they aren't their child after raising the kid for some time as their own, and turning into an abusive (non-biological) father or simply becoming cold towards their supposed kind. It can also apply to the legitimate half-sibling if they feel contempt for their bastard half-sibling for "ruining their parents' marriage" by being a symbol of the affair.
- Bokura no Kiseki: Glen is the bastard child of the head of the noble Belbania family and a servant, but because his stepmother is dead during his childhood, it's his older brothers and other nobles who feel disdain for him and his mother. The truth is more complicated, as he's actually a Child by Rape by another noble, and his adoptive father made up the cover story to protect him and his mother. The stepmother knew this and feels nothing but sympathy for them.
- Maid-Sama!: Takumi Ushi is treated with contempt by his legitimate half-brother Gerard Walker, primarily because he's an illegitimate child due to their mother's affair with the butler, along with blaming him for his mother's death. He warms up to Ushi later on, but Ushi still has a strained relationship with his biological family.
- In Saiyuki, Gojyo's stepmother despised him for being both her husband's bastard and a half-youkai. She was constantly abusive to him, which came to a head when she tried to kill him with an axe and her own son killed her to prevent it.
- The Flash: George Harkness, the first Captain Boomerang, had a frosty relationship with his father who always treated him badly, which he blamed for his Jerkass behavior. At his mother's funeral Harkness' father reveals he was actually the result of his mother cheating on him, and that's why he never liked him. Harkness proceeds to decapitate his "father" over the reveal.
- Played with in Gene Luen Yang's post-TV-canon Avatar: The Last Airbender comic The Search. For some time, Zuko, Azula, and the reader believe that Ozai's cruelty to Zuko was because of Urza's confession that Zuko wasn't his son. The ending reveals that Ozai knew all along that Urza had been lying to try to get to him, but that he still abused Zuko in order to punish her for lying to him.
- Played with in Bastard!!: Gil Alien is born after his mother's brief affair with Gilderoy Lockhart, and his mother's husband Jonathan (whom Gil refers to as "stepfather") vents his rage about the fact at Gil all the time. However, when Gil gets stuck in the past with no hope of return, he realizes Jonathan didn't hate him as much as he seemed to, acknowledging Gil as his son legally, raising him as carefully (if more angrily) as his own children, sending money to Gil's Gringotts account so that the boy wouldn't be penniless when he comes of age, and giving him a dangerous but exciting job that Gil thoroughly enjoys.
- Conqueror: Genghis Khan is racked with insecurity and doubt over the parentage of his son Jochi. Jochi may have been conceived while his wife was abducted and the prisoner of a rival; his wife maintains Genghis is the father and she was treated with honor and decency while she was a hostage and was neither raped nor unfaithful. Genghis has doubts and this sours his relationship with his son, who tries to be loyal and faithful, but who eventually rebels and deserts him.
- A Song of Ice and Fire: In Westeros, it is considered acceptable for men to have bastards, and also acceptable for their wives to abuse said bastards.
- Lady Catelyn Stark resents Jon, her husband Ned's bastard son. It's not so much his existence that really bothers her, but the way that her husband brought him home and and insisted on raising him alongside Catelyn's trueborn children and treating him better than most bastards in their world are treated. Catelyn can live with the fact that Ned had a bastard—they had only recently gotten together when Jon was born anyways—but she perceives the way he treats Jon as a reflection of some love and loyalty to Jon's mother. The fact that Ned absolutely refuses to talk about it, or tell her anything about Jon's background, doesn't help. Still, despite it all, she treats Jon a lot better than most other women treat their husbands' bastards. By Westerosi standards, she went beyond the call of duty by letting her husband raise Jon under the same roof as her trueborn children, give him the same education and upbringing, and did not interfere with Jon having close relationships with his father and half-siblings.
- In the Shield Islands, Lady Hewett made her husband's bastard daughter a servant for her and her own daughter.
- Cersei is a zigzagged example, is that her husband having bastards doesn't make her hurt or jealous, but it does make her embarrassed, and upset after some fashion. Her marriage is a loveless one, with both of them cheating on the other, and both of them having bastard children. She doesn't mind that, really—all the sex he has with others means less Marital Rape License for her. But when her husband's bastards were too visible—for example, when he had a bastard in her hometown—she found it humiliating, and had the bastard killed.
- Possibly inverted with King Aegon IV the Unworthy and his son and successor Daeron II. The two never got along because Daeron was responsible compared to Aegon's hedonistic and inept rulership, and it's said he may not have been his biological son, rather being the product of Queen Naerys's affair with Aemon the Dragonknight. However most historians believe that Aegon made up the idea Daeron was a bastard born out of his wife's affair because he already hated him, and wanted to disinherit him since he preferred his own bastard Daemon Blackfyre to him.
- Chronicles of the Kencyrath: Pereden and his consort Distan—Pereden's parents. We don't meet Distan until after Pereden dies, but they seemed pretty happy together—at least, Distan clearly adored him. He Really Got Around though, and that clearly hurt her. She takes it out on his bastard son Drie.
- This is mentioned in The Camp Half-Blood Series, where demigods are the result of extramarital affairs by default. (See Classical Mythology below.)
- True to form, Hera despises her husband's demigod daughter Thalia, although her Roman form Juno is more forgiving towards Thalia's brother Jason.
- Persephone and Hades's kid Nico have a strained relationship, with her turning him into a plant at some point.note Persephone: [coldly] We had a little family spat.Nico: Family spat? You turned me into a dandelion!
- Subverted in My Next Life as a Villainess: All Routes Lead to Doom!: After Katarina ends up getting engaged to prince Gerald, her father adopts the son of a distant relative named Keith to act as his new heir. Katarina's mother, not knowing of Keith's origins, comes to the conclusion that he is actually her husband's bastard child (though she is right about him being illegitimate, as his mother was a prostitute). In the original timeline, this led to her becoming verbally abusive towards him. Thanks to Katarina having thrown everything Off the Rails in the story proper, she learns the truth rather quickly and instead acts as a loving mother for him.
- Classical Mythology: Zeus Really Gets Around, and has a lot of bastards. It really bothers his wife Hera. She's the goddess of marriage and childbirth, making every one of Zeus's affairs a stain upon her domain. She can't do much against Zeus himself due to his position and power outranking her, so she takes it out on his lovers and bastards. Take Heracles for example: Zeus names him Heracles specifically to try to appease her and defy this trope... but she's not having any of it, and tries to have Heracles killed at least once.
- Shining Song Starnova: Nemu Akimoto is the illegitimate child of the heir of Amaterasu Television. When her biological mother died her father's wife Haruna treats her with scorn for being a reminder of her husband's infidelity, and won't let her follow in her mother's footsteps by becoming an Idol Singer.
- In Dragon Age: Origins, it's explained that Arl Eamon's wife Isolde treated Alistair like crap because she thought there was some truth to the rumors that Alistair was actually Eamon's illegitimate son, and she eventually pressured her husband to send Alistair away to the Templars. Whether there was any truth to Isolde's fears about Eamon sleeping around behind her back or if she was just a Clingy Jealous Girl is never made clear, and it's revealed early on in the game that Alistair's father was actually King Maric so either way she was in the wrong.