I will try to keep this brief because it could become convoluted and confusing very quickly. After some genuine opinions on what (if anything) I can do.
I have a very close group of 6 female friends from university (15 years ago) who see each other a few times a year but chat very regularly on WhatsApp (at least a few times a week). The group chat can be very candid as you would expect from old friends. A few months back one of the friends 'B' confessed to us (in confidence) that for years she had been living a kind of double life- multiple relationships/ jobs/ personas. Although the details were surprising to us, none of us were THAT surprised- she is a very compartmentalized person in every respect. She said she was very ill (suicidal) from it and had stopped now to address it through counseling. None of us judged or gave an opinion- it wasn't what she needed at the time. And of course we all agreed to keeping secret whilst she worked out what to do.
Fast forward a few weeks and the husband ('E') of another friend of the group was out with my DH (all the husband's get on well). My DH said after a few pints E came straight out and said he had been going through his wife's phone (!) and had read the whole thing. He clearly hadn't actually read it all properly or in any great detail as he seems to have got some of his facts wrong. My DH told me all this and was upset that E had mentioned it- I had not told him about B's confession and he was glad I hadn't. My DH does not want to be involved at all.
So now I am stuck. B was in the wrong for her actions BUT E shouldn't have gone through the phone. B + her husband and E + his wife sometimes socialise together and I hate the thought of him knowing her secrets simply because he was sly enough to mistrust his wife. I sort of want to tell her to "even it up".
Sorry it is long... WWYD in my position?