You may be making several assumptions. You described your behavior as narcissistic and abusive, but this may or may not be true. For instance, you stated that you were often critical of others but not because you felt superior to them. Narcissists notoriously feel superior to everyone.
You’re also assuming that she joined a narcissist abuse group because of you. She could have joined because of a friend or a family member. You could have been the impetus but unless you ask her, you simply don’t know.
What is your motivation for wanting to write to her? Are you simply wanting to apologize? Are you trying to rekindle the relationship? What is your goal?
Whatever your goal, you can try sending her a letter or an email. Explain why you wrote the letter.
Finally, be prepared for the possibility that she might not reply. Will it matter to you if she doesn’t reply? If your goal is to apologize and to be sincere in your apology, then it would not matter much if she replied or did not reply. At least you’ll know that you did everything you could to express your remorse. Please take care.
Dr. Kristina Randle