What was the stress in the relationship with your ex in the relationship around finances, power, control, etc.?
It seems to me without knowing more, that there may have been some difficult issues with him in the past and may have been unresolved...at least unknowingly unresolved and they are coming up when the mind is supposed to be at rest but often this is the time that things get worked through.
I am here to continue the conversation when you are ready.
How can I support you?