My father in law and his friend kind of caught me in a bad way?

I'm not much for confessing sins to a spouse - BUT there wasn't any sin. Please tell your husband about what happened - get it off your chest. You had every right to expect privacy and from what you've said they weren't intentionally violating your privacy - it just happened. Where's the guilt? You wish it wouldn't have happened - so - big deal. Tell your husband.