This article addresses clinical and ethical directions in treating clients doping with infidelity. Developing competence in this domain requires familiarity with empirical research regarding infidelity, individual and cultural differences involving nonmonogamy, and assessment and intervention skills related to treating infidelity. Practical directions will entail distinguishing
among responsibilities to individual partners versus their relationship and managing related potential conflicts of interest with other involved parties.

Confidentiality assumes increased complexity when confronting undisclosed infidelity in couple therapy and when a client engaging in high-risk behaviors for contracting STDs or testing seropositive for HIV has not informed his or her partner(s). Finally, we discuss therapists’ need to concretely articulate their values that influence treatment of infidelity. © 2005 Wiley Periodicals, Inc. J Clin Psychol/In Session 61: 1453–1465, 2005.