When: September 2007 - December 2007
Before he began dating Jennifer Aniston and before she linked up with Mr. 3,000 himself, Derek Jeter, Mayer was rumored to be dating the adorable Minka Kelly. The relationship didn't last long, and it's said that Mayer was actually the one who ended it. Yes, you read that right, Minka Kelly was dumped. Wow.
Smash Probability: While we doubt most John Mayer dates end in a peck on the cheek and an "I'll call you next week", he did break up with her. Perhaps she was playing hard to get?