What is the ruling for a husband who falsely accuses his chaste wife (muhsana) of adultery?

Primary text

If a husband falsely accuses his chaste wife of adultery, the prescribed legal punishment (hadd) is obligatory upon him, his testimony is rejected due to being declared a transgressor (fasiq), unless he brings four witnesses or engages in the solemn oath of mutual imprecation (li'an). If he fails to bring four witnesses or refuses the li'an, all these consequences—the hadd, the declaration of transgression, and the rejection of testimony—are incumbent upon him. This view is held by Malik and Al-Shafi'i. The basis for this ruling is the Divine Statement: "And those who accuse their wives and bring forth no witnesses except themselves, then the testimony of one of them shall be four testimonies..." [Quran 24:6] indicating that only li'an is established for spouses in this context. However, the comprehensive evidence is the verse: "And those who accuse chaste women and then do not bring four witnesses, flog them eighty lashes and never accept their testimony afterward; and those are the defiantly disobedient [fasiqin]" [Quran 24:4]. This applies generally to the husband and others; the husband is specified only because his li'an substitutes for testimony, thereby negating the hadd, the declaration of transgression, and the rejection of testimony. Furthermore, the Prophet, peace be upon him, stated, "Evidence, or the hadd upon your back," and upon engaging in li'an, he said, "The punishment of this world is easier than the punishment of the Hereafter."