It sounds to me like this song is about a troubled relationship in which the singer finally takes things too far and his partner leaves. He seems to be apologizing for whatever he did, and essentially saying that he had no idea what he did would cause her to leave and hurt their relationship as much as it did. He just wants to take whatever he did back and to get things back to the way they were before he screwed up. It's just a really sweet song that goes to show you never know what you have until it's gone.
It sounds to me like this song is about a troubled relationship in which the singer finally takes things too far and his partner leaves. He seems to be apologizing for whatever he did, and essentially saying that he had no idea what he did would cause her to leave and hurt their relationship as much as it did. He just wants to take whatever he did back and to get things back to the way they were before he screwed up. It's just a really sweet song that goes to show you never know what you have until it's gone.