Maybe when you stop writing about her/him,
When every dead letter is no longer addressed to her/him.
When you stop hoping that she/he is the recipient of your bottled up feelings as a message in a bottle.

Or maybe,
You will not.
A part of them will always linger, she/he will be braided with your emphatic soul.
She/he will be the ember that slowly fades with the darkness, but still remains as remnant ashes.
Maybe you just learn to unlove her/him.
But deep down you know,
you will always love her/him.
She/he is,
Sempiternal.