What are the cases of men’s 'Iddah (post-marriage waiting period)?

All perfect praise be to Allaah, the Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

All Muslim legists believe that a man is not required to undergo ‘Iddah i.e. post-marriage waiting period to remarry after divorcing his wife; for he can remarry directly after the divorce without waiting for his wife to complete her ‘Iddah i.e. post-marriage waiting period. This is so unless there is another reason that prevents him from remarrying then; such as if he wants to marry his divorcee’s paternal or maternal aunt or any other relative of hers to whom he cannot be married at the same time that he is married to his wife. Also, if he divorces one of his four wives and wants to marry another one; then, he has to wait until the ‘Iddah of the revocable divorce ends according to the consensus of Muslim jurists and that of the irrevocable divorce according to the majority of Fiqh (Islamic jurisprudence) scholars.  ‘Iddah i.e. the post-marriage waiting period in Arabic, is derived from the concept of counting; for this period would last for several months. On the other hand, idiomatically i.e. in Islamic Fiqh terminology, ‘Iddah means the post-marriage waiting period which the divorcee spends so as to make sure that she is not pregnant or out of submission to the command of Allaah The Exalted to her to observe it or to mourn  over her deceased husband. Therefore, based on this definition, the cases when men are banned from marriage cannot be called ‘Iddah; since it can not bear either the linguistic meaning or the idiomatic meaning. However, some have called these periods ‘Iddah exceptionally to mark the similarity between the case of a divorcee and a husband when he divorces one of his four wives and wants to remarry. In fact, there are many occasions when it is impermissible for Muslim men to marry, such as during Ihraam, or due to illness; however  such cases cannot be called ‘Iddah.   

Allaah Knows best.