My Girlfriend's Boyfriend (2010)

Ethan Reed (Christopher Gorham) is a struggling writer who unsuccessfully tries to publish his manuscripts through Barbara (Carol Kane), and therefore is forced to manage a flat for a second living. After yet another rejection, Ethan decides to quit writing, and drinks off his defeat in a caf?. There, he meets Jessie (Alyssa Milano), a divorced waitress who lives with her brother David (Tom Lenk). After a conversation, he gets up the nerve to ask her out. Shortly after he leaves, an attractive and confident advertising executive, Troy (Michael Landes) comes in, and he asks out Jessie as well.

Jessie thought she has met the right man in Ethan, and is now in over her head when she meets Mr. Right a few seconds later.