Of course, sexual affairs are red flags for infidelity, but there are common elements that make any outside relationship an infidelity. Sex therapist Tammy Nelson explains what they are and how to spot them.

By Jon Carlson - Couples therapists need to be aware of the strategies that prevent relapse, so that short-term successes don't become long-term failures, and to address those areas in the initial therapy with the couple. However, if gains are not maintained, here are five areas of treatment you may need to revisit.

By Margaret Nichols - In past decades, the only alternatives to involuntary celibacy in a relationship were affairs or divorce. But increasingly, people, including therapists, are recognizing there’s another option: consensual nonmonogamy. The idea isn’t new, but nonmonogamy is threatening to a lot of therapists for the same reason it’s threatening to most people: we instinctively want to believe that these unconventional relationships are flawed.

By Molly Layton - The longer I practice, the more I'm struck with the importance of tolerant, hovering attentiveness that looks, Janus-faced, both outwardly at the client and inwardly toward the therapist's own processes.

By David Schnarch - Over the years, I've worked with many couples who complain bitterly that the other kisses or touches, fondles, caresses, strokes the "wrong" way. These couples need to understand that the ways they show physical affection is a remarkably salient and authentic expression of themselves and their feelings for each other.

By George Faller - Many of our clients, especially men, believe in the traditional definition of vulnerability: a state of weakness that leads to being open to attack. But vulnerability is the language of emotionally connected beings, and like a powerful magnet, pain, doubt, fear, mistrust, and other vulnerable states bring forth new opportunities for deep intimacy and transformation, especially in work with couples.

By Michele Weiner-Davis - How is it possible to do couples therapy with just one partner? We clinicians communicate our presuppositions about people and how they change when we do our work. If we begin therapy with a "this is better than nothing" attitude, we undoubtedly broadcast a pessimistic message about the possibilities for change.

By Gay Hendricks - Therapists who understand and apply two concepts about commitment—that the results you get reveal the actual commitment you've made, and to make a change in a relationship, each participant must take 100 percent responsibility for the current situation—can eliminate a great deal of energy-draining work in the treatment of couples.

By David Treadway - Over the years, the couples in my practice who’ve actually done homework exercises have reported communicating better and being more affectionate and more supportive of each other than couples who haven’t. To make sure I’m successful in motivating them, I use these six techniques.

In a world of new and emerging norms about commitment, intimacy, the right to personal happiness, and open relationships are there also new patterns? Has the truth about adultery changed? In the following video clip, Helen Fisher, author and scientific advisor to Match.com, gives us the answer.