She lied about something in her relationship, but that doesn't mean she lied about everything to her husband. Nobody has been completely honest with their spouse at all times - does that make them all dishonest people, or does it make them people who have been dishonest? Clearly the latter, that's reality.
If this goes on much longer, I may need to take a bath. Listen, I believe in sacramental confession with a priest that takes away sin. If an adulterer makes it right with God, great. And the people they've offended can forgive them, too.
But if someone's got an obvious, flapping moral weakness that has her putting Old Number One ahead of principle, it does her no favors to put her in the way of temptation. I might send a card on Mother's Day, but put my money elsewhere. Prudence is a virtue.