Who knows that heart?

It's who I used to love,
I don't remember the love,
My head remembers the days,
But my heart has forgotten the aches,
It has no memory of pains,
But I know of the steps it takes,
Always away,
It won't settle down,
And now no light and no dark nights would make it move,
I know not what guides the heart,
But it ain't the love it used to have,
It ain't the pain it could suddenly remember,
Slightly confused, I have enquired the mind,
But we have found no clue at all.