It should be confidential, BUT your H OW is going to go like this "I got the weirdest phone call today..." and since he listens to her, he will say "Oh, really what happened?"
So you see where this is going, then you have OW and H pitted against you because your causing them problems. You are drawing the circles and placing them in one and you in your own alone. Think like this, do you want him in your circle or her circle? If it is your's are you doing something that he will respond positively too.
When is the last time on TV, real life a book, whatever, the person playing your H said "Why Thank you for snooping on me, I'm so glad you caught me so that we could live happily..."
They don't they scream and yell, you've ruined his trust. It sucks but they are selfish ego stroking idiots right now, with no logic and heart. Just back off and see what happens.