Marie – happily married for 15 years, with 2 children – discovers that her husband Jean is having an affair. Once the initial shock has passed, she decides to meet her rival, Virginie, and make her an awkward proposal: that they share joint custody of Jean. Virginie agrees and the two women introduce him to this new way of life. What seems like a dream come true – one week with his wife, one with his mistress – might well prove less than perfect for Jean…