I dont think that you ever really let go of someone you love. Physically, yes, they are no longer with you, but emotionally, in your heart there is always a part of it that stays with you.
Its a fact of life that feelings change. It is unevidable, like the leaves changing in the fall, or the sun setting. People grow, apart or together, but not always the same when they are a couple.
Emotional ties keep us forever bonded even after we have said goodbye. Tears are shed and hearts are broken. The only thing we can ever really do to let go is to hold onto the memories that tie us together. Remember the smiles and the laughs. The warmth of each others embrace, opposed to the hurt and the tears.
Whether it be the break up of a relashionship, or the passing of a loved one, we let go, in the only way our hearts know how to, in a way that each of us only knows how to, to suit ourselves. But for me, the only way i can truely let go is to remember that I was happy. To remember that I loved, and for a time was loved back. I remember the way I smiled at the thought of that first kiss, or they way he looked at me when I said I love you with such pride. I remember being happy, and that for me, can get me past the worst heartache.