I think that he is just talking about two parts of himself. His ID is broken into two distinct parts, Love and Hate. He pities himself for not being able to stop hating. The hating side of him knows that he has glimpsed love but couldn't allow it to take over and fill his life with light. I don't think that anyone else will ever know the meaning of this song, unless Corey Taylor lets us know. There are glimpses of duality in the video where he is the dark part and she is the light, but then at the end, she is him. The other people in the video notice the change and are taken aback. These lyrics are very heartfelt and can mean so many different things according to your own experiences. There likely is no wrong interpretation. I do have another theory that he is actually singing to 2 different people involved in this song, but I haven't taken the time to try to break the parts apart. The bottom line is that this song is epic. It should last for all eternity; it is just that good.