Eddie Cantrow (BEN STILLER) is the 40-year-old owner of a sporting goods store in San Francisco. He's yet to find true love, however, much to the dismay of his father, Doc (JERRY STILLER), and best friend, Mac (ROB CORDDRY). That is, until he meets Lila (MALIN AKERMAN), an attractive environmental researcher.
The two immediately hit it off, but she then gets word that her company is going to transfer her overseas. Hearing that they wouldn't if she were married, Eddie decides to take the plunge. The two get hitched, and then head off to Cabo for their honeymoon, where Eddie is to deliver a package to resort worker Uncle Tito (CARLOS MENCIA).
It's there, however, that he learns of her sordid past -- including a coke habit -- as well as her wild nature in bed, massive mood swings, and the general ability to irritate him to no end. During one of their breaks away from each other, Eddie ends up meeting lacrosse coach Miranda (MICHELLE MONAGHAN) who's there vacationing with her family.
Sensing she's the true woman for him, but unable to tell Miranda he's married, Eddie then tries to figure out how to spend time with her away from Lila, and get up the nerve to break up with his wife, all while Miranda's cousin, Martin (DANNY R. McBRIDE), becomes increasingly suspicious of Eddie. From that point on, a series of comedic misunderstandings complicate matters for him.