No - I agree with you Puppy that he does look for this possible problem. I just think the focus has to be on the 180s and looking for what is wrong first.
So what if he found there was an EA/PA? Now what? For her to leave the EA/PA, doesn't she have to have something to come back to?
If he got caught snooping, what would he say? I asked my W once if she was thinking about anyone else. She said no. I accepted that. Had she felt I was spying/snooping, we'd just have less trust to work with between us.