Movie about a guy who receives a mysterious list of all his girlfriends, past and future

I watched a movie a few years ago, and now can't remember the title.

The main character received a mysterious email at work containing a list of every woman he had, or would have sex with--past and future.

I can provide more details if necessary, but I'm sure this will be enough for anyone who's seen the movie (and remembers the title) to identify it.