I want to caution you that the apology letter which was sent in March 2014 happened nearly after 9 years after our split. During the intervening years, we both slammed the door in our faces at various times during "reaching out" moments. Ms. Wonka was as tough and slow as a glacier and I worked very, very hard to chip away at it.
You might want to file away the apology letter later for the "right time." I do think it is important that you do acknowledge your W's email to you for it was heartfelt regardless of how 25 interpreted it.
What is important now is to distill her email to you and reflect on them for they do contain nuggets of truth for you since they are her feelings and POV. Try to see you through HER eyes and I think you might be able to gain some fresh perspective on her pain along with her fear of getting hurt by you again.
In my mind, in your situation, I think it is critical that you at least acknowledge her feelings and respond with 2 to 3 short paragraphs. Not acknowledging them would be more of the same from you in blowing off her feelings and diminishing her as a human being. No need to write War & Peace in your response trying to defend or explain yourself!
Meanwhile, use the gift of the time to reflect on your behaviors, thought patterns, and attitudes. Then make any changes that YOU want to make FOR YOURSELF. You want to get to a place where you feel better about yourself and get to a healthier place of relating with others--especially women.
It starts with you right now. The choice is up to you.
