I Love You, Man (2009)

As his wedding day approaches, Peter Klaven (Paul Rudd) realizes he has no one to act as his best man. Through a series of "man-dates," he finds Sydney Fife (Jason Segel), and the pair become instant friends. But as Peter's "bro-mance" with Sydney grows stronger, it threatens his relationship with his fiancee (Rashida Jones), forcing Peter to make a choice.