To me this is about letting someone back into your life, even though in the past they have hurt you. And even though you know, in the back of your mind, that this person is poison to your life, you keep letting them back in because of how much you love them. However, you eventually come to admit that this person is just bad for you and you become flooded with a bunch of emotions you haven't felt before and because of this you can finally move on with your life.
To me this is about letting someone back into your life, even though in the past they have hurt you. And even though you know, in the back of your mind, that this person is poison to your life, you keep letting them back in because of how much you love them. However, you eventually come to admit that this person is just bad for you and you become flooded with a bunch of emotions you haven't felt before and because of this you can finally move on with your life.