During a counseling session, a client who is notably upset about spousal extramarital affairs discloses...

When a client discloses an intention to harm someone, counselors are ethically and legally required to take reasonable steps to warn the potential victim and/or notify authorities. This is known as the "duty to warn" (from the landmark Tarasoff v. Regents of the University of California case). The counselor must breach confidentiality if there is a clear threat of violence to an identifiable person.