Confidentiality and the Ministry Spouse: by PW

One of our constant readers and commenters is “PW”, who is helping us think about the issues surrounding the spouse of a minister — not always a female, we add. Do you tell your spouse everything? What do you keep back? What rules do you use? Now on to PW:

This has happened more than once in my life as a ministry spouse: I have had people stop me in the hallway of the church and start to talk to me about something that was confidentially discussed between them and the pastor (my spouse). I had no clue what they were talking about. In one case, you could see by the look on the person’s face that it just occurred to her that I was not privy to her discussion with my spouse.
 
I know for a fact this could happen to executive spouses and people in other professions. How do you handle confidentiality with your ministry spouse? Or your professional spouse?  We have a policy to keep confidential things confidential unless there is reason to first get permission to discuss it with our spouse.