I don't mean to be harsh. Therapy is about the client and not the therapist, and the relationship is not a friendship. And her getting married is very personal. Unless it effects your working with her (closing the practice, relocating the practice), she does not need to mention it. I am sorry if this sounds rude/harsh, but those are the boundaries of therapy.

I feel for you. I've wanted personal information about another therapist that I used to have, but I had to remind myself that he was my therapist and we weren't friends.