Relationship counseling is the process of counseling the parties of a human relationship in an effort to recognize, and to better manage or reconcile, troublesome differences and repeating patterns of stress upon the relationship. The relationship involved may be between members of a family or a couple (see also family therapy), employees or employers in a workplace, or between a professional and a client.
Couple's therapy (or relationship therapy) is a subset of relationship counseling. It may differ from other forms of relationship counseling in various regards including its duration. Short term counseling may be between 1 and 3 sessions whereas long term couples therapy may be between 12 and 24 sessions. An exception is brief or solution focused couples therapy. In addition, counseling tends to be more 'here and now' and new coping strategies the outcome. Couples therapy is more about seemingly intractable problems with a relationship history, where emotions are the target and the agent of change.
Marriage counseling or marital therapy can refer to either or some combination of the above.
The methods may differ in other ways as well, but the differences may indicate more about the counselor/therapist's way of working than the title given to their process.