Trixi - they don't necessarily have an affair - and sometimes it isn't the major theme. It seems to be a part of MLC at some point for most spouses. And that is about as defnite as it gets!
They are in escape from marriage/ escape from current life mode - which makes it hard to distinguish from WAS.
I think the touchstone is uncharacteristic behaviour, rather than an affair. They change into someone unrecognizable as our spouse - Alien eyes, Pod people, is how they are often described. They espouse opinions they never formerly held . . . and so one. Read the resource threads if you haven't already.
I was pretty sure it was MLC, but wasn't finally sure until last February, 15 months post bomb, when we went to therapy because h thought I was crazy, and the therapist told me it was MLC, in his view, and then my h was very lost. H moved out [5th time] the next day and I have seen him once since.
