Senescalcus
From The Seven Sages of Rome
AdulteryMoney in exchange for promise of sexHomosexualityIllnessDeceitful advisorDeceptionMistaken or concealed identity
The Steward (for comparison, see this story's analogue, Balneator)
A king falls ill due to some abberation with his sexual activities, usually identified as a hatred of women or homosexuality. He is told that the only cure for his illness is for him to sleep with a woman. He instructs his steward to find a woman to sleep with him, whom he will pay handsomely. Wishing to keep the reward for himself, the steward convinces his own wife to sleep with the king, and leads her to his chamber in darkness. After the king has slept with the wife, all is revealed and the steward is shamed.
Note
This story is a close analogue of Balneator, found in the Eastern branch of the tradition.