Starring Alison Brie and Jason Sudeikis. Rated 14A.

Just last year, David Wain’s They Came Together became the Scary Movie of rom-coms, ticking off friends-with-benefits boxes with Paul Rudd and Amy Poehler subverting, or at least mocking, the genre knowingly at every When Harry Met Sally turn.

For a while, Sleeping With Other People seems to be following a similar arc, but the new film’s attempt to get serious actually pays increasing emotional dividends as it moves along. That’s mostly due to the concentrated chemistry of Mad Men’s big-eyed Alison Brie in a star-making turn as Lainey and SNL veteran Jason Sudeikis as Jake. They’re fast-talking New Yorkers who happen to lose their virginities to each other in college and don’t meet again until both attend (what else?) a sex-addiction meeting.

He’s a compulsive cheater who’s developed a killer app, which has no bearing here except that it allows him the free time to be in this story, and the opportunity to hit on his new boss, played by Amanda Peet. Lainey keeps her unhealthy obsession pretty much focused on one guy, an about-to-be-married gynecologist (Adam Scott) who occasionally fits her into his stirrups.

These two sad sexters spark again but agree to avoid actual ugly-bumping, knowing that each will lose his or her most sympathetic ear. Yeah, we know how that’s gonna go. Still, writer-director Leslye Headland keeps things at a foul-mouthed boil, restraining the harsher impulses that made her 2012 Bridesmaids rip-off, Bachelorette, even less popular than They Came Together. When Jake gives Lainey an illustrated disquisition on female masturbation, it should be a disaster but instead becomes a performance-art high point.

Unfortunately, the Will Ferrell–produced movie soon reaches its own natural climax, and then goes seriously bonkers in the last 10 minutes, glomming on to all the mistakes it had avoided up until then. Well, there must be a meeting for that.