Taylor Swift and John Mayer first met at 2008 Met Gala on May 5, 2008. Swift was a fan of Mayer's music. After meeting him at the Met Gala, Swift talked about it to People: "I was star struck by the fact that he came up and introduced himself to me, I was like freaking out!" Taking advantage of the chance encounter, Swift immediately started referencing Mayer's popular blog. "I just respect him so much, I was rattling off quotes that he said in his blog, and he was probably like thinking that I'm a stalker," she laughed. "But he was amazing and sweet."
In March 2009, Mayer said he'd like to collaborate with Swift in a song. In May 2009, Mayer joined Swift on stage and they sang "Your Body Is A Wonderland" together. They kept tweeting to each other friendly throughout 2009, including tweets of Swift calling him her "hero". Mayer's fourth studio album "Battle Studies" was released on November 17, 2009, featuring "Half of My Heart", a collaboration of Mayer and Swift. They performed it together at Z100 Jingle Ball on December 11, 2009. Later that month, sources reported that Swift and then boyfriend, actor Taylor Lautner, had broken up. Dating rumors between Swift and Mayer sparked after that, with sources claiming she dumped Lautner to date John Mayer. Back then, she was only 19, meanwhile Mayer was 32.
Swift attended Mayer's concert in Franklin on January 26, 2010. They were also allegedly together at the Ritz Hotel in Dallas on March 9, 2010. It seems that they broke up later that month, or in the next month. However, Mayer presented Swift at 41st Annual Songwriters Hall of Fame Ceremony on June 17, 2010, and earlier that June, they had an awkward run into each other at the CMT Awards.
The romance was unconfirmed until Swift released her album "Speak Now" in October 2010, which includes infamous "Dear John". Other songs from the album are also supposedly about Mayer, such as "The Story of Us", "Superman" and "Ours". Mayer has spoken a few times about how he was unhappy with the songs Swift has written about him, especially "Dear John". It is rumoured that, as an response to this song, Mayer wrote "Paper Doll".
In an issue of Glamour magazine, in 2012, Taylor called John Mayer "presumptuous" for saying that he was "really humiliated" by "Dear John" lyrics. She went on to say that she did not want to hear his comments about the song, because of her desire to stay happy: "I know it wasn't good, so I don't want to know. I put a high priority on staying happy, and I know what I can't handle. It's not that I'm this egomaniac and I don't want to hear anything negative, because I do keep myself in check, but I've never developed that thick a skin. So I just kind of live a life, and I let all the gossip live somewhere else. If you go too far down the rabbit hole of what people think about you, it can change everything about who you are."
In October 21, 2022, Swift released her tenth studio album "Midnights" that includes "Would've, Could've, Should've", a song that is seemingly about her past relationship with Mayer. Looking back at their past relationship's consequences, Swift recalls how their relationship left her haunted, and also how she regrets it to this day. "God rest my soul/I miss who I used to be/The tomb won't close/Stained glass windows in my mind/I regret you all the time"