Consensual nonmonogamy (CNM) means that all partners in a relationship consent to expanded monogamy or polyamory. Clinicians are on the front line in providing support for the estimated millions pioneering these modern relationships. This first available guide for therapists provides answers to prevalent questions: What is the difference between expanded monogamy and polyamory? Is CNM healthy and safe? Why would someone choose the complexities of multiple partners? What about the welfare of children? Through illustrative case studies from research and clinical practice, therapists will learn to assist clients with CNM agreements, jealousy, sex, time, family issues, and much more. A Therapist’s Guide to Consensual Nonmonogamy serves as a step forward toward expanding standard clinical training and helps inform therapists who wish to serve the CNM population.