I asked my husband on a number of occasions to NOT tell my MIL a particular piece of personal information about me. I thought he understood my reasons, namely that she is prone to asking intrusive questions, would have to stick her oar into a very private matter and can't keep a secret to save her life. (The first thing he told me about his mum when we met over twenty years ago was not to trust her with anything I wished to remain private so you'd think he'd understand.)
Yesterday, I found out that he has passed on the private information I told him I wanted kept between us. I discovered this by walking into the room while he was on the phone telling her that she has to remember not to pass this information all around family, friends etc!
I confronted him to be told that it just "Slipped out" while talking to her! Seriously?! Right now I am so hurt and angry I can barely control myself. I made it so clear that my private matter was to remain private, I told him explicitly not to tell her. I feel let down, betrayed, furious.
He thinks that I should just forgive him as it was an accident, apparently. I say, if your wife asks you to respect her privacy regarding something, that should be fairly important.