Witold Gombrowicz’s (very) short story “The Tragic Tale of the Baron and His Wife” is up at The Paris Review (translation by Tul’si Bhambry). First section of the story—
The Baroness was a charming creature. The Baron had taken her from a family of high principles and had no reason to mistrust her, despite the fact that the tooth of time had already gnawed into him quite deeply . . . And yet a disquieting element of grace and charm lay dormant within her, which could easily complicate the practical application of the Baron’s imponderabilia (since the Baron was a bit of a stickler). One day, after a period of conjugal life graced with the quiet bliss of marital duty, the Baroness came running to her husband and threw her arms around his neck. “I think I ought to tell you this. Henryk has fallen in love with me . . . Yesterday he declared himself to me, so quickly and suddenly that I had no time to stop him.”
“And are you in love with him, too?” he asked.
“No, I don’t love him, because I have pledged my love to you,” she replied.
“Very well then,” he said. “If you are in love with him but do not love him because it is your duty to love me, then my esteem for you doubles and I love you twice as much. And the young chap’s suffering is a well-deserved punishment for his weakness of character—losing his heart to a married woman! Principles, my dear! Should he ever make another declaration of love, tell him that you also have a declaration to make—but of principles. A man of unshakable principles can walk through life with his head held high.”