What Happened?

I never thought I'd see the end of you and me
We both said "I guess it's meant to be"
I thought we'd always be together
You even said, "I'll love you forever!"
The best days of my life were spent with you
But it was one day when you made me feel blue
You finally decided to let me go
I asked "Why?"
And you said "I don't know"
I still wonder 'What happened? What did I do?'
And I say to myself 'Nothing, just leave him he wasn't for you'