If a man threatens to expose an illicit relationship that occurred between him and a married woman to her husband, what should the wife do if her husband asks her to swear an oath of divorce and questions her about the relationship? And does the divorce take effect if she lies to him to avoid scandal?

The most important thing to do is to sincerely repent to Allah, frequently seek forgiveness, and pray for the acceptance of your repentance and the forgiveness of your lapse. You must also sever all contact with this criminal. Allah will avert his cunning and malice from you, for He says: "Indeed, Allah defends those who have believed" and "And whoever fears Allah - He will make for him a way out." It is not to be thought that he will carry out his threat; rather, it is a means of pressuring you. If your husband asks you and swears by divorce for you to tell him the truth, lying is not permissible. Instead, you must tell him the truth that you have repented, and that informing him came after you had refrained from him.