This is one of those French movies that may not translate well for Americans. Most American movies dealing with marital infidelity usually end with someone's death as in movies like Unfaithful, Fatal Attraction, or the sinning spouse going back to the marriage. Our puritanical background, perhaps? Culturally speaking, we tend to hold that the wages of sins is death.
The French have a more nuanced view of the subject, and this movie reflects it perfectly well.
Excellent performance by all the actors, even direction, honest dialogue. This movie is to be enjoyed with an open mind.