All of John Mayer's Famous Girlfriends

The pair dated on and off between 2012 and 2014. They seemed to stay on good terms, with John admitting he's sent Katy happy birthday wishes since their split, and Perry even once named him her best lover during an appearance on Watch What Happens Live. Katy is now engaged to Orlando Bloom.

Mayer must be a Friday Night Lights fan! He started dating Kelly towards the end of 2007.

Dating Simpson from 2006-2007, it's hard to forget his crude comments to Playboy magazine about the starlet where he referred to her as "sexual napalm."

Swift penned a song titled Dear John which Mayer (and the rest of the world) assumes is about him. He told Rolling Stone magazine that he was "really humiliated" by the track. The two were rumored to have had a fling from Nov. 2009-Feb. 2010.

Dating off and on between 2008 and 2009, in an interview with Rolling Stone magazine, the "New Light" singer said he had "never really gotten over" his breakup with the Friends star.

Dating in 2002, it's speculated that Mayer wrote Your Body Is a Wonderland for The Client List star.