The main character of this song (not necessarily T. Swift) is telling us this tale. However, instead of feeling sorry for her, she comes off pathetic for putting up with the mistreatment.
And consider the dumpee's point of view of the guy. He obviously didn't think that much of the main character. He used her (when it was convenient for his schedule) and then got HER to break things off - he didn't have to be the bad guy. So the main character is sure to slander him. She is stuck on all the things he did. He probably moved on while she can't yet.
The main character of this song (not necessarily T. Swift) is telling us this tale. However, instead of feeling sorry for her, she comes off pathetic for putting up with the mistreatment.
And consider the dumpee's point of view of the guy. He obviously didn't think that much of the main character. He used her (when it was convenient for his schedule) and then got HER to break things off - he didn't have to be the bad guy. So the main character is sure to slander him. She is stuck on all the things he did. He probably moved on while she can't yet.