In my opinion, this song is about a relationship that isn't going so well and both of them know it.
She isn't surprised/hurt/upset when they break up because she saw it coming a long time ago.
"We sat next to the fire
As the flame was burning out
I knew what you were thinking
Before you'd say it aloud"
And that even though he tries to apologize and say that he's sorry about what happened, she knows it's just for show and that she knows him well enough to know when he's lieing. Basically she's like "if you don't care about me, I don't care about you."
In my opinion, this song is about a relationship that isn't going so well and both of them know it. She isn't surprised/hurt/upset when they break up because she saw it coming a long time ago. "We sat next to the fire As the flame was burning out I knew what you were thinking Before you'd say it aloud" And that even though he tries to apologize and say that he's sorry about what happened, she knows it's just for show and that she knows him well enough to know when he's lieing. Basically she's like "if you don't care about me, I don't care about you."