The early, awesome stage of romantic relationships, characterized by firehose neurochemistry, socially off-putting behavior and a lot of chafing, eventually diminishes into bored, sexless collegiality, open bathroom doors, and socks in bed. Love has an agenda (babies) and once a couple checks that action item off the to-do list, biology returns to its zero-point ground state of microwaved Stouffer’s dinners and episodes of The X Factor. That’s what happens to literally every marriage, every single time, without exception, the end. And it’s certainly what’s happened to Agathe (Isabelle Huppert), a bad-tempered art dealer, and her publisher husband, François (André Dusollier), in director Anne Fontaine’s My Worst Nightmare. Their son befriends the child of an aging slacker/carpenter named Patrick (Benoît Poelvoorde), whom they reluctantly hire to finish the remodeling of their coitally disused bedroom. François invites the builder to move into an attic room, and under Patrick’s good-time party influence, he winds up dating a beautiful, zip-lining social worker 30 years his junior while Agathe’s overbearing demeanor uncurdles and reverts to a younger, more emotionally accessible state. A state that involves a lot of wine drinking and spontaneous hookups, as it turns out. Poelvoorde’s physical performance, involving falls, crashes through walls, crass language and comedic mugging, contrasts with Dusollier’s refinement and discomfort with social impropriety. And Huppert combines a middle-age woman’s new embrace of hedonism and dick jokes with deeply ingrained resistance to her own bad behavior. Whether this is an argument for or against marriage probably depends on the viewer’s own experience.