Distance sounds wise....need not be dramatic or a conflict....just a respectful sort of pulling back while wishing her peace. She's clearly in pain, right? Happy people don't treat others that way. So I admire that you have no desire to add to her pain....just peacefully drawing a line. Best wishes as you navigate that and keep us posted if you feel like it.

Forgot to say, I did try to discuss the issue with my former friend. She looked stunned and denied it entirely. My therapist thinks she may well have been unaware of her own insecurity and maladaptive coping response. I should also say she's not a "bad" person by any means. She's just a bit mixed up and I wish her peace and happiness from afar.