Where is the reason why?

Where is the sunshine inside my heart?
Why is it now I'm falling apart?
I walk around and act like toy don't exist
Yet deep in my heart the ache persists.
I was your wife friend your cherished one
The one who brought u joy when no one could.
On those rainy days we'd hold each other close
On those cold nights you stayed by my side.
I'm not perfect but I was perfect for you
And now I don't exist I'm just a burden a woman you used to know.
And though in my heart the hurt is going away.
You cheated on me too and why didn't u stay?
She stays when you lied and she treated you like shit.
I walked away cause you didn't push for me to stay
We could have fixed it. If you weren't afraid to try.
And now all I can do is ask myself a sad and lonely why!