I found this interesting about 20 years ago when I first read it. Might be worth a review.
THE ETHICS OF DUAL RELATIONSHIPS
by Karl Tomm
First paragraph follows/
In my opinion, the AAMFT Ethics Committee and the AAMFT Board are attending to the wrong
issue in actively discouraging dual relationships in the field of family therapy. The focus in the AAMFT Code of Ethics should remain centered on the avoidance of exploitation and not be shifted onto the avoidance of dual relationships. I acknowledge the importance of finding ways to protect the dependency and trust of clients. However, a more specific means of doing so is required than simply avoiding dual relationships. An ethical injunction to avoid duality not only fails to address the xploitation that occurs within professional relationships, it introduces some of its own problems.
This is indeed a classic article, that was published many years before the field has changed. As my summary at http://www.zurinstitute.com/boundariesbrochure.pdf clarifies, Dr. Tomm was a head of his time.
Ofer Zur, Ph.D.
Director, Zur Institute