Originally Posted by valinors_sorrow
I think snooping is always wrong, even in marriage. There is never a right time to do a wrong thing. Admitting to a suspicion and warning someone that they are on notice for further scrutiny is the only above-board way (and I site this as a method for, say, a parent with a child they suspect of drug use). As a result she has now seriously handicapped her ability to have a frank, open, and honorable discussion about her gut feelings with him... which is what should have taken place to begin with.
It's that old adage: two wrongs don't even each other out or something to that effect.
Although this is likely to be an unpopular suggestion, I advise she live with the discomfort on the email as the price of snooping. When she has tangible evidence that backs up her gut reaction without resorting to actions that compromise her integrity, then she can bring up the discussion by limiting it to that evidence.
Otherwise, her only other recourse is to confess to the snooping to confront him with what she found and be prepared for his indignation. Sounds like an "all the cards on the table" from both sides type of conversation is really overdue here.