Lyrics from snippet

I like to forget how the pieces fall together
Separating the timelines makes me feel a bit better
I like to pretend I believe that you respect me
We just met at the wrong time and she came along after me
And I’m glad that you found what you need

But if we’re talking technically, then you were mine first
All my ugly parts search for the right to hate her
But I’m sure she doesn’t know who I am
‘Cause why would you bring up your old backup plan?
And I guess that makes sense if I don’t think too hard
So I guess I’ll pretend for the sake of my heart
That you weren't mine first