I think this song is about being left (in a relationship) for anothers ex.
Who obviously hurt them to become an ex,whom they never got over.
They go back to the ex,and then complain to you about how they are being treated.
"So if you're treated badly now, I'd scarcely be surprised
You're seen for what you really are, it's time you realized"
and she takes the role as a friend who holds some unrequited love/bitterness over this.
"And if I ruined your life I'd be filled with pride
Yet I could not harm you even if I tried"
I think this song is about being left (in a relationship) for anothers ex. Who obviously hurt them to become an ex,whom they never got over. They go back to the ex,and then complain to you about how they are being treated.
"So if you're treated badly now, I'd scarcely be surprised You're seen for what you really are, it's time you realized"
and she takes the role as a friend who holds some unrequited love/bitterness over this.
"And if I ruined your life I'd be filled with pride Yet I could not harm you even if I tried"
just my interpretation.