When my xah was laying on the guilt like you describe I finally went no contact to everything except emails. I only responded to the one's about the kids that were about logistics - ignored the one's that threw around blame, guilt, and some other form of manipulation. If I would have had a good friend I'd have had her read them first before me so I wouldn't have had to even read the garbage ones. It really went a long long long way in helping me to reach a level of detachment and clarity.
Wishing you the best...