I do not Love you except because I love you

I do not love you except because I love you;
I go from loving to not loving you,
From waiting to not waiting for you
My heart moves from cold to fire.

I love you only because it's you the one I love;
I hate you deeply, and hating you
Bend to you, and the measure of my changing love for you
Is that I do not see you but love you blindly

Maybe January light will consume
My heart with its cruel
Ray, stealing my key to true calm

In this part of the story I am the one who
Dies, the only one, and I will die of love because I love you
Because I love you, Love, in fire and blood.

-Who is this by?