Billboard seems to have a summary of each of her (sometimes just rumored) relationships, and the songs that sprang from their fall-outs. I also found additional songs from a Suggest.com listicle, the List of Taylor Swift's ex-boyfriends page on the Taylor Swift Wikia, and I'm not sure how accurate any of these sources are, but they each seem to provide at least some evidence for their claims, so it's at least a starting point.
High School Boyfriends
- Jordan Alford — Left TSwift for one of her friends
- Brandon Borello — Left for college and they broke up
- "Tim McGraw"
- "Our Song"
- "Fifteen"
- Sam Armstrong — Cheated on TSwift
- Drew ??? - Never actually dated Taylor, she just liked him
Post-fame Boyfriends
Note that some of these are rumored romances without official confirmation from TSwift. In order from first to last, we have:
- Joe Jonas — July 2008 - August 2008
- "Last Kiss" — negative and right after the breakup
- "Forever And Always" — also negative and right after the breakup
- "Better Than Revenge" — about the girl that Joe Jonas left TSwift for
- "Holy Ground" — more recent and also positive
- Lucas Till — March 2009 - April 2009
- No known songs about that relationship
- Taylor Lautner — August 2009 - December 2009
- "Back To December" — features TSwift apologizing to a guy she was with, one with "tan skin" and a "sweet smile", so this is rumored to be Lautner
- John Mayer — December 2009 - February 2010
- "Dear John" — about the older John Mayer not treating her as well as she would have liked
- "I Knew You Were Trouble" — May have been about him, may also have been about Harry Styles
- Cory Monteith — April 2010 - May 2010
- "Mine" — It apparently has never been confirmed that they were dating, but it seems like that this song was about Monteith
- Jake Gyllenhaal — October 2010 - January 2011 —
- "The Last Time" — rumored, though unconfirmed, that this is about Gyllenhaal
- "All Too Well" — apparently TSwift spent Thanksgiving with the Gyllenhaal family...
- "We Are Never Getting Back Together" — Also rumored but unconfirmed
- "State Of Grace" — Also rumored but unconfirmed
- "Girl At Home" — Also rumored but unconfirmed
- "The Moment I Knew" — Also rumored but unconfirmed
- Eddie Redmayne — October 2011 - January 2012
- This relationship is also unconfirmed, and there don't seem to have been any songs about Redmayne
- Zac Efron — February 2012 - March 2012
- Another rumored/unconfirmed relationship with no known songs, Efron and TSwift did do a parody of the rumors in a cover of "Pumped Up Kicks" on Ellen Degeneres's talk show
- Conor Kennedy — July 2012 - October 2012
- "Begin Again" — rumored that this is about TSwift's relationship with the younger man
- Harry Styles — December 2012 - January 2013
- "Style" - Sounds like his last name... Coincidence?
- "Out of the Woods" — widely assumed to be about Styles because it references a December romance and a snowmobile accident
- Adam Young — Never dated
- "Enchanted" — TSwift met the Owl City frontman, but he was super shy at the time, and later sent a note apologizing; she responded to the note with this song