Does a divorce oath made falsely to prevent harm to others take effect, and what is its expiation, and what rights does it entail for the wife?

Whoever swears an oath by divorce falsely, his divorce takes effect. The fear of harm has no bearing on the occurrence of the divorce. One must repent from swearing an oath by divorce because it is an oath of the wicked. Furthermore, lying is forbidden unless it is necessary to achieve a benefit or avert harm. In this case, if averting harm from the man cannot be achieved except through lying, then we hope there is no sin in it.