"I know you know that I made those mistakes maybe once or twice. By once or twice I mean a couple hundred times" could refer to urinating in the mop bucket, egging a house, being drunk, or cheating on Selena with a bunch of other girls. "I'm missing more than just your body", "But you know there is no innocent one in this game for two", "Can we both say the words and forget this?", and "I'm not just trying to get you back on me" show how he let Selena down. The rest of the song could apply to him either letting us or Selena down.
"I know you know that I made those mistakes maybe once or twice. By once or twice I mean a couple hundred times" could refer to urinating in the mop bucket, egging a house, being drunk, or cheating on Selena with a bunch of other girls. "I'm missing more than just your body", "But you know there is no innocent one in this game for two", "Can we both say the words and forget this?", and "I'm not just trying to get you back on me" show how he let Selena down. The rest of the song could apply to him either letting us or Selena down.