Abigail Williams from The Crucible fits this trope like a glove. After her boss John Proctor ends their affair, Abigail jumps at the opportunity to have his wife Elizabeth arrested and executed for witchcraft. It backfires big time. Elizabeth's pregnancy keeps her from being executed; John takes the blame upon himself and chooses execution over admitting witchcraft and losing his land, which would leave his family homeless.
The Phantom of the Opera: Erik, the eponymous Phantom, towards Christine. Erik captures Christine's lover and gives her the choice of being with Erik forever or watching her lover die. Ironically Christine chooses Erik which snaps him back to sanity and he frees them both to be together.
In the theatrical sequel Love Never Dies, Meg Giry has become one: she has fallen in love with the Phantom, now her employer at a pierside show in Coney Island, New York. When she sees how much he still loves Christine, Meg goes insane and kidnaps Christine's son, leading to a rather ... explosive finale.
Jackie-O from The House of Yes. She kills her twin brother, whom with she has been having an incestuous relationship for most of their lives, when he attempts to regain a life of normalcy with his utterly average fiancee.
Canio from Pagliaccilearns that his wife Nedda is cheating on him, and loses it. At first, the audience thinks he's giving a very emotional performance, but soon realize this is for real. Canio kills Nedda and Silvano and gives a Bond One-Liner.
Salome, the Princess of Judea at the time of Jesus, is this toward Jokanaan (John the Baptist) in both the play and the opera about her. Whenever she's around Jokanaan she can't stop saying "I want to kiss your lips!" When he, predictably, wants nothing to do with her so long as she remains uninterested in Christianity, she uses a seductive dance to trick her stepfather, Herod, into giving her "anything she wants," which ends up being Jokanaan's severed head on a plate.
Depending on the interpretation, The Governess from The Turn of the Screw. This only works in the interpretation where The Governess is insane, the ghosts are not real, and she has the hots for Miles, killing him to protect him from corruption.
Bluebeard, for Judith and all the other women he kills and keeps forever.