Something Wild (1986)

Free-spirited Lulu (Melanie Griffith) sets her sights on uptight banker Charles (Jeff Daniels) for a little bit of fun. Their relationship starts off simple enough with a tryst and some modest adventure, but Lulu wants Charles to pose as her husband at a high school reunion. It seems harmless enough to Charles, but that all changes when Lulu's actual husband, Ray (Ray Liotta), confronts them at the event. Understandably, Ray isn't content to let Charles and Lulu ride off into the sunset.