"Saying goodbye is Death by a thousand cuts" means that she is having trouble saying goodbye to something. "You say this is a great love, one for the ages. But if the stories over, why am I still writing pages?" Means that she probably thought that this was going to be the one to go down in history, but she is confused that why they still are in a relationship after they broke up. "...I ask the traffic lights if it will be alright, they say I don't know." Meaning that she is trying to rekindle the relationship, but this time she is taking it slow avoiding what other people say like if it is good running across that red light or slowing down at a green light.