Let's simplify things. . . your last statement is that you do not want to change therapists. So, you either trust your therapist to not break confidentiality or you have to accept that he may or may not have told his wife (your boss) that you were a client. Hopefully, if he did tell his wife that you were a client, the discussion ended right there.

The only way you are going to straighten this out and either get your trust restored or not is to approach this subject as honestly as you can and openly share with him what you have shared with us. Give him the whole picture of how it felt walking into the break room, etc.

This whole situation is about whether or not you can trust your therapist and in my opinion has very little to do about your boss. As you said, she seems to be a nice person.

A little reality testing: If your boss knew you were in therapy with her husband how would this change your job performance? Perhaps she would feel proud that you chose her husband as your therapist because he is so accomplished.

It's easy to get stuck in ruminating over the negative aspects and play the "what if?" game. The bigger challenge is putting the "truth to the lie". You could just as easily say to yourself, "who cares if my boss knows I see a therapist - many people see therapists". 0R you might have to draw a boundary and say, "I am not willing to see a therapist who I feel I cannot trust not to tell his wife about our sessions".

Confronting your therapist may feel very upsetting, however, I think that any professional can see the potential pitfalls in this situation and would be very compassionate towards your fears.