And the step father wants to keep me informed to protect me, and I do believe him.
I'm trying to figure out just how exactly informing you of your AXF's status is protecting you.
I can definitely see it if she's been physically abusive towards you and her presence threatens your safety. I can certainly see how, in a strange way, it must provide some consolation to you that her misguided affair and her addiction has become evident to so many people.
But if she doesn't present a physical danger, I'm still stuck on the word "protect". The best way to protect yourself from further emotional abuse at this point is, IMHO, to block all further communication.