Actually, Lightbody wrote this song after he cheated on his girlfriend, so its really about that and the mistakes he's made. He is reflecting upon the experience and he regrets the decision he made. In a way, he's apologizing to her, while at the same time accepting full responsibility for his actions. He wants to start new, but that will always hang over his head. That's what the song is about.
Actually, Lightbody wrote this song after he cheated on his girlfriend, so its really about that and the mistakes he's made. He is reflecting upon the experience and he regrets the decision he made. In a way, he's apologizing to her, while at the same time accepting full responsibility for his actions. He wants to start new, but that will always hang over his head. That's what the song is about.