I cannot imagine me ever believing it is appropriate for a spouse to tattle to a therapist. If the spouses involved have discussed the situation and have asked their spouse to contact the therapist in certain situations - then good for them. But without that, it does seem blanketly inappropriate to me. The therapist I see is not someone for my partner to use to express their concern, fears, information, point of view etc. That is for them to do with their own therapist or friends or diary. In my opinion.