I hope that you are able to rebuild that trust. It's a pretty significant error on his part. My therapist has done some way out there things as well. Sigh.

For me the key to getting back to the relationship is to make absolutely positively sure that he has heard and understood why you are bothered. You have every right to expect him to be responsive to it.

While he may view his staff as an extension of himself, you do not. Nor should you. His response that he will fire the person if they violate confidentiality, to me, indicates that he still may not understand how you see it.

This is a relationship, not a result from a laboratory test. It makes a difference.