GW,
I understand. The grieving is difficult, old M and possibly no new marrige. You will be OK.

I have similar difficulties with the STBXW continuously bringing up the past. It seems to me that it is script for them, and justification for their actions with the A, a way to ease their own guilt and pain.
It sounds like you are not getting transparency, did she agree to totally clean?
If not, I bet she is still cake eating with OM.