The Tao of Steve (2000)

In college, Dex was the big man on campus. Ten years later, now an overweight kindergarten teacher, Dex is immune to the shocked stares of the women who were once his conquests. While trying to pick up the bartender, he is struck by the gorgeous Syd. Through a series of circumstances, Syd and Dex are thrown together and he soon finds himself questioning his belief in all things Steve.