Seeing Other People (2004)

"Get it out of your system."

Ed and Alice are two months shy of getting married when she realizes that she wishes she'd had a more active love life while still single. Reluctantly, Ed agrees to have an open relationship in the months before their wedding, and initially this seems to improve their connection, particularly in the bedroom. However, as Ed and Alice get more involved in their own flings, the experiment goes awry.