Paris doctor Catherine starts to think her husband, Bernard, is having an affair when she hears an unfamiliar woman's message on his voice mail. Hoping to learn more about his extramarital activities, Catherine heads to a strip club, where she hires call girl Nathalie to have a fling with Gerard. As the affair progresses, Nathalie gives Catherine regular status reports, and the relationship between the women evolves from business to personal.
56:00 The wife () meets a bartender at a party and comes with him to his place. He starts kissing her on the neck as they are about to climb the stairs in his building, but their sex is just implied as the next scene immediately proceeds to the next morning where she is walking away from his place.
1:13:38 The wife sees the call girl () servicing her client in a sort of foursome.
1:34:21 The wife and the call girl look at each other and it looks like they are about to kiss but they just hug. They may still have had implied sex after that but I'm just guessing.
The husband seems to be faithful as I didn't see him get successfully seduced by the call girl, but I could be wrong.
I haven't seen Chloe (2009) (US remake) yet but based on its trailer, it does seem to have sex scenes between the wife and the call girl.