This is how I think it's played. I hope it's correct.
For the walkdown bit I suggest that you play an open A-chord using one finger so
that you can hit the G# note on the bass e-string in the A/G# chord
A F#m C#m
Nothing like a memory to open up a broken heart
G F#m E
Its been years but i look at you now and we’re torn apart
A F#m C#m
Nothing like a face to take you back to the time
G F#m E
When it was you and i against the world just you and i
D E
And i wish it hadn’t happened to us
A A/G# F#m
You fell in love with that girl
D E
And i wish it hadn’t happened to us
A A/G# F#m
You fell in love with that girl
D E
And i wish it wasn’t true
A A/G# F#m
But all you cared about was the girl
G F#m E
Nothing like a lover to set you up for a fall
You’re feeling you’re ready to die like you lost it all
Nothing like you and i in that place in time
And it’s so hard letting you go ’cause you’re still on my mind
And i wish it hadn’t happened
But you fell in love with that girl
I wish it never happened to us
You fell in love with that girl
And i wish it wasn’t true
But all you cared about was the girl