Peter, Most people didn’t know that their marriage was in trouble until BD. Even if it wasn’t great we just thought that was how marriage was supposed to be ups and downs. It is likely you W was slowly checking out for years. Someday you will probably look back and see it. Right now you are in the forest and can’t see the tree. She meets OM and boom her attitude changes. She has to pick fights because she has to make it seem she is leaving an awful marriage.
In our sitch, I'd say she might have been "checking out" (meaning increasing unhappiness in this case, getting closer to an undefined low threshold), for about 8 months, max, and obviously increasing after IC started. During BD, and several times after that, she herself told me that D was unthinkable "even 2 months ago". She has revised 2021 quite a bit and I understand this is natural pre-D behavior, so I don't hold the revisionism against her even though some of it is rather hurtful.
But her affections over the phone were real and communications normal even the day before she met OM. Less than 14 days later she decided to D. That is a fact. It's the day that she took the A drug and our lives went upside down, without ever seriously talking maturely about the state of our MR among ourselves or even considering MC. Not that any of this matters much now, but it is useful for context.
