A marriage therapist works with married and engaged couples only. The therapist works with these couples on their relationship. Most of a marriage counselor's clients are already married and are experiencing a problem in their relationship. The problem they need help addressing could be due to a variety of factors. Some of the most common problems marriage therapists see clients for are cheating, affairs, money problems, problems with children, and intimacy or sexual issues. For example, a couple may try marriage therapy if the husband has cheated on his wife with a coworker. Or, marriage therapy may be in order if the couple is having a hard time adjusting to having children. Marriage therapy may help one or both partners work through the issues they have with sex. Many couples consider marriage therapy to be a last resort before divorce.

Sometimes, engaged couples seek out a marriage therapist. These couples are interested in working through any issues they may have before they get married. Some people think this makes for higher chances of having a successful marriage. The therapist will talk to these clients individually and in group settings, trying to identify any problems that may only get worse with marriage. For example, if the bride-to-be has past issues with a relationship that she has not gotten over, the marriage counselor will try to address these issues and resolve them before the wedding takes place.