I'm very surprised indeed that nobody has read Maupassant on this forum so I'm going to assume that the review(s) were lost in one of the many crashes.
This is absolutely superb. Superb translation of a superb story. It concerns a painter called Olivier Bertin who makes a name for himself in Paris and lives rather comfortably, with staff, in his batchelor pad. He's very popular for portraits and social occasions. He has a long running affair with the Countess de Guilleroy, the wife of a busy politician. It's never made clear if the relationship is sexual, though. Everything is fine until the Countess's daughter - Annette - turns 18 and comes back from school to be married. Then the painter and the Countess are each seized by an agonizing suspicion, like death. . . .
The prose is amazing, the philosophy is profound and the observations of human behaviour are razor sharp. We are told that the Countess works extremely hard to keep the painter interested in her as she is aware that he leads a lonely life and may marry in order to off set that. He is flattered by her attentions and in love so it suits both of them, until Annette comes home and everything changes.
I read the NYRB (New York Review of Books) edition and it was translated by Richard Howard.