It’s not within Christian principles to do what you are doing.
These sorts of thoughts are a waste of time.
Assuming that she should have better moral standards because of her religion is a cheeseless tunnel.
Aetheists do good things, and bad things.
Christians do good things, and bad things.
During the initial stages of my separation, my ex wife would take the children on her weekend and sit in church singing and praying - while she was actively having an affair.
I think overall you handled the interaction very well.
The person you thought you knew doesn’t exist. Either never did, or is missing in action (likely for many years).
Set your expectations of her very, very low - it makes your life easier.
The only person whose thoughts and behaviours and morality you control - are yours!
