John Mayer,Taylor Swift dated notorious ladies’ man John Mayer from November 2009 to February 2010. The breakup left Swift heartbroken and she penned the song “Dear John” about it. Some have speculated that Swift lost her virginity to Mayer, as the brief relationship really did a number on Swift’s heart when he broke off the relationship. We now know that Mayer had more groupies and female flunkies to attend to.