I get triggered also. Could be mail from the AH, or from his attorney. Could be an email from someone who knows us both.
I can tell you emphatically that I do NOT ever intend to go back to that way of living, I do NOT miss living in that insanity, and I've not ever missed it at all.
So, for me it's definitely a PTSD type thing, from living with the stress for so long. Heck I still have the stress, dealing with the aftermath of marrying an abusive scumbag.
What I want from therapy is a way to detect abusive scumbags before they become MY abusive scumbag. Though he was my first, so maybe I'll spot them now, dunno.