My heart breaks for you to have to carry such a love destined to be unrequited.  The romantic in me wishes the two of you could have another chance, but the realist doubts that can ever be.  She was too hurt by you.  Even now across distance and time, you still have the power to touch her, if only to mortify her.  Still there exists some strange undying connection which refuses to release her and obviously you as well.

My inclination to tell you to go to her is strong though misguided.  I would only wish to see the wounds of two I care for healed, the spiritual scars faded.  I yearn to tell you to go to her, to take her once more into your arms and erase the pain, the fear, the hurt.  Would that you could undo the terrible injury you rot within the beauty and innocence of her soul.  I fear I would be doing both of you a disservice with such advice.
She has spent her life suffering from the pain you placed inside her.  She has spent her life eradicating any part of you from within her heart.  She has spent her life learning to live somehow with all that was ripped from her by your careless youth and wandering ways.  She has spent her life searching for the safety of one that might provide her haven to mend the spirit you so carelessly assaulted.
Such is the waste of love that a thing so precious and pure can so often be abused by the reckless young.  I see you both struggle through your lives neither truly happy, neither ever complete again.  Can such harm ever be undone?  If you knew then what you know now, would you have had the strength to contain your wanton desires and protect that precious gift she offered?
Should that you have sincerely changed from that imprudent young man, she is no longer the ingenuous girl you damaged without thought.  She may labor to put you and all you represent into a box never to be re-opened.  Still, she has learned well the way of leaving you behind.  It is as second nature to her now.  She finds some peace in the arms of another.  She has made her choice and is reclaiming those things you once stole from her.
This is no cosmic prank, but karmic debt due.  Such it is that we reap what we sow.  Love is a fragile bloom.  Your wild oats sprouted a garden of weeds that choked out the delicate flower that once could have blossomed there and made your life whole.  This your harvest is all that is left to you.  Pittance for the ocean of tears you caused her, small price your one last tear.