Don Quixote Volume 1, Chapter 33
The story is about two best friends named Anselmo and Lothario who lived in Florence. They were both single noble gentlemen and rich. Anselmo falls in love with a girl named Camila and marries her. One day Anselmo confides in Lothario that he cannot be sure that his wife Camila is as virtuous and wonderful as she seems unless he puts her to a test.
He explains that if his wife is only chaste because she has had no chances to be otherwise, he cannot value her as much as if she had been tempted and resisted. He wants Lothario to flirt and attempt to seduce her. His friend is shocked -- Anselmo seems like a stranger to him:
"It seems to me utterly clear either that you do not really know me, or I do not really know you." Volume 1, Chapter 33, pg. 218
Lothario is appalled that Anselmo would ask him to do such a despicable thing and tries to speak some sense into his friend. He tells him his wife is only human, and shouldn't be tested but protected from temptation. Also, what would Camila think of Lothario, if he insulted a friend this way? Lothario refuses, but when Anselmo admits that he is so obsessed that he is going to do this with or without his friend's help, he relents. Anselmo says that if Lothario would just flirt a bit with Camila (test the waters) and she responds honorably, that will satisfy him. Then they can tell her this was a test cooked up by her husband and Lothario will not look dishonorable.
Lothario figures out a way to trick Anselmo and not have to do this insulting thing to Camila. Each time after Anselmo returns home (after leaving on some trumped up excuse to leave them both alone), Lothario makes up details about how boldly he flirted with Camilla and how she showed no interest and even threatened to tell her husband if he didn't stop. Still not satisfied, Anselmo wants his friend to offer her money and jewels! Unknown to Lothario, Anselmo spies on them this next time and finds out that Lothario is lying to him and not even speaking to his wife when he leaves them both alone.
Lothario tries to reason with him again. But, Anselmo won't listen and arranges a trip away for himself and tells Camila that Lothario will keep an eye on her and the house and eat there and she should treat him like her husband! She says that she would prefer a chance to prove that she was capable of running the house in her husband's absence, but Anselmo tells her that she has been told what he wants, now all she need do is "bow her head" (pg. 226) and obey him.
And so, Anselmo and his insatiable ego leave. Lothario arrives, and despite his good intentions is starting to become enamored with the lovely Camila after spending so much time in her company. His loyalty and affection for his friend are replaced by anger that Anselmo should place him in such a tortuous predicament. After three days Camila's maid, Leonela, (despite her mistress's orders that she is to stay by her) leaves her alone with Lothario who suddenly and passionately and truly starts trying to seduce the lovely Camila. She sends a note to her husband.