Does a man have to observe ‘iddah?
Question

When does a man have to observe ‘iddah? What is the wisdom behind that?
Praise be to Allah.A man does not have to observe ‘iddah; rather ‘iddah is only for women, whether it is ‘iddah following divorce or following the death of the husband. But the man is to be prevented from marrying a fifth wife until the ‘iddah following divorce of his fourth wife has ended. He is also to be prevented from marrying the sister, paternal aunt or maternal aunt of his wife until her ‘iddah has ended. But this should not be called ‘iddah [in his case].
Al-Hattaab (may Allah be pleased with him) said in Mawaahib al-Jaleel (4/140): As for describing as ‘iddah the period during which the husband is prevented from marrying after divorcing his fourth wife or divorcing the sister of the one whom he wants to marry, or anyone else to whom he cannot be married at the same time as the wife whom he is divorcing, that is undoubtedly by way of analogy, but it should not be included under the same heading as the ‘iddah that is prescribed in Islamic teachings [for women]. And Allah knows best. End quote.
In al-Mawsoo‘ah al-Fiqhiyyah (29/306) it says: With regard to a man waiting until the end of the [woman’s] ‘iddah: the fuqaha’ are of the view that ‘iddah is not required of the man, because it is permissible for him to marry someone else after separating from his wife, without waiting until her ‘iddah has ended, unless there is some impediment that prevents that, such as if he wants to marry her paternal aunt, maternal aunt or sister, or anyone else whom it is not permissible for him to marry when he is still married to his wife, or he has divorced his fourth wife and wants to marry another, in which case he must wait for the ‘iddah of a revocable talaaq to come to an end, according to scholarly consensus, or even that of an irrevocable talaaq, according to the Hanafis, in contrast to the majority of fuqaha’, in which case he does not have to wait. Preventing the man from marrying in this case is not called ‘iddah, either in a linguistic sense or in Islamic terminology, even if it looks like ‘iddah. An-Nafraawi said: The purpose of ‘iddah is to prevent the woman (from remarrying  too soon), and the period during which a man who has divorced a fourth wife is prevented from marrying someone else cannot be called ‘iddah, either in a linguistic sense or in Islamic terminology, because the man may be prevented from getting married in many situations, such as during ihram or when he is sick, and no one would describe him as observing ‘iddah in such cases. End quote.