In working with relationships, I take much the same approach as I do with individuals. Cognitive Behavioral Therapy sees the RELATIONSHIP as the patient and not the INDIVIDUALS in the relationship! While this might sound odd at first, think about it. The reason people in a relationship see me is that there is a problem (maladjustment) in the RELATIONSHIP. So Cognitive Behavioral Therapists treat the relationship as they would an individual. The additional benefit to this is that no member of the relationship feels as though they are being singled out or sided with.
After the intake session and description of the problem, for the next couple of sessions, I have the couple describe the problems they have, rank them in order of importance to the effect upon their relationship, and then assign brief homework that lets me help evaluate each member of the couple's thinking. I also observe the interaction of the couple with both themselves and me.
Once this is done, I evaluate the level of cognitive distortion for each member of the couple. This allows me to pinpoint where each member of the couple's level of cognitive distortion is and if there are cognitive distortions between them that are causing the problems in the relationship. At this point, if I feel that one or more of the people in the relationship have a clinically significant level of maladjustment, I offer that person individual therapy in addition to relationship therapy. The reason behind this is that if a member of a couple has significant maladjustment, it is very unlikely that the relationship can improve unless this is addressed.
Finally, as with all my areas of therapy, I look for problems in communication. In relationship therapy, most often there is a significant problem in communication. It is just far more obvious in relationship therapy because the people trying to communicate are doing so right in front of me.
This is where my additional graduate work in communications comes into most often. By observing both verbal and non-verbal communications, quite often I can pin down the problems in relationships fairly rapidly if they are related to the members' communication with each other or others.