Taylor apologizes in this song about the way she messed up a relationship with a former boyfriend, who now finds it hard to trust her. According to the Back To December Songfacts, the song is dedicated to an actual person to whom Taylor feels she had done wrong. It is the first time she has apologized to someone in a song. It's rumored to be about Taylor Lautner.
Taylor Swift also explains the story behind "Back To December" on her official website: .