Thihaar
It is that a man says to his wife, "You are (unlawful) for me as is my mother." According to many scholars, the same is valid if the mention of the mother is replaced with the mention of anyone of his Mahrams (non-marriageable women) like his sister or daughter. Islam prohibits Thihaar. It makes a man’s wife unlawful for him, if it is effectuated, until he makes expiation for it. Thihaar is not considered divorce as it was during the pre-Islamic days, nor is it considered among the number of divorces. Rather, it is an oath by which a man’s wife becomes unlawful for him. Allah The Almighty Says (what means): {Those who pronounce Thihaar among you [to separate] from their wives - they are not [consequently] their mothers. Their mothers are none but those who gave birth to them. And indeed, they are saying an objectionable statement and a falsehood. But indeed, Allah is Pardoning and Forgiving. And those who pronounce Thihaar from their wives and then [wish to] go back on what they said - then [there must be] the freeing of a slave before they touch one another. That is what you are admonished thereby; and Allah is Acquainted with what you do. And he who does not find [a slave] - then a fast for two months consecutively before they touch one another; and he who is unable - then the feeding of sixty poor persons.
That is for you to believe [completely] in Allah and His Messenger; and those are the limits [set by] Allah. And for the disbelievers is a painful punishment.} [Quran 58:2-4]
Khul‘
It is a right given to the wife who is unable to observe the right of Allah The Almighty concerning her husband, due to dissention and disagreement between them. She should give back to her husband all that she has taken from him, unless he accepts from her less than what is due. Allah The Almighty Says (what means): {But if you fear that they will not keep [within] the limits of Allah, then there is no blame upon either of them concerning that by which she ransoms herself. These are the limits of Allah, so do not transgress them. And whoever transgresses the limits of Allah - it is those who are the wrongdoers.} [Quran 2:229]
It is narrated on the authority of Ibn ‘Abbaas, may Allah be pleased with them, that the wife of Thaabit ibn Qays ibn Shammaas, may Allah be pleased with him, came to the Messenger of Allah and said, "O Messenger of Allah! I could not find any fault with his morals or religion. But I hate (the morals of) disbelief in Islam (i.e., she dislikes him and detests to live with him out of aversion she has towards him.)” The Messenger of Allah said to her: "Then, will you give him back his garden?" She answered in the affirmative, thereupon, the Messenger of Allah said (to Thaabit, may Allah be pleased with him): "Accept the garden and divorce her once." [Al-Bukhari and An-Nasaa‘i]
‘Iddah (Post-marriage waiting period)
It is a limited period of time which varies according to the different conditions of the woman, during which it is unlawful for her to marry. It begins from the very moment her husband leaves her, either by divorce, death, or the like. The women's different post-marriage waiting periods are:
1- The ‘Iddah of death: The woman whose husband dies and leaves her even without consummating the marriage with her should fulfill a post-marriage waiting period of four months and ten days, i.e. nearly 130 days, in compliance with the statement of Allah The Almighty (what means): {And those who are taken in death among you and leave wives behind - they, [the wives, shall] wait four months and ten [days].} [Quran 2:234]
The same applies to her, whose husband dies after consummating the marriage with her provided that she is not pregnant.
However, if she is pregnant, her ‘Iddah remains in effect until she gives birth. If separation is caused by both divorce and death, then, if the divorce is revocable, after which the husband dies, the woman should move (from the ‘Iddah of the divorced) to the ‘Iddah of such as whose husband dies, according to her condition whether or not she is pregnant.
2- The ‘Iddah of divorce and the annulment of marriage: If she is divorced before consummating the marriage, no ‘Iddah is due upon her. If she is divorced after consummating the marriage with her and she menstruates, her ‘Iddah is three menstruations, in compliance with the Aayah in which Allah The Almighty Says (what means): {Divorced women remain in waiting for three periods.} [Quran 2:228] However, if she does not menstruate, like a young girl, or the woman in the age of menopause, her ‘Iddah is three months in compliance with the Aayah (verse) in which Allah The Almighty Says (what means): {And those who no longer expect menstruation among your women - if you doubt, then their period is three months, and [also for] those who have not menstruated.} [Quran 65:4] If she is pregnant, the term of her ‘Iddah is until she gives birth, no matter how long or short the period might be as confirmed by Allah The Almighty where He Says (what means): {And for those who are pregnant, their term is until they give birth.} [Quran 65:4] If a woman who menstruates is divorced and then her menses cease for an unknown reason, her ‘Iddah is a whole year.
The child’s custody
The Messenger of Allah gave the right of the child’s custody, whether it is a male or female, to the mother so long as she does not get married. Ash-Shaafi’i estimated the period of custody of the male child until seven years. However, according to other scholars, there should be no particular age at which the custody terminates. But, what should be taken into consideration is the child's ability to become independent in terms of managing his affairs, and once he is able to do so, he should be in the care of his father. Others prolong the period of custody to the age of puberty. As for the female, she should wait with the mother until she reaches the age of puberty, after which she should be put under the care of her father. But, according to the Hanbali school of Fiqh (Islamic jurisprudence), she should be put under the care of her father at the age of seven, in order for her to have more protection.
As for the ruling in case the child is in the age of discernment, it is debatable among the scholars of Fiqh. The Shaafi‘i scholars give the child the freedom to choose between his parents. But the Hanbali and Maaliki scholars were of a different opinion. According to those of the Hanbali school of Fiqh, in order for the freedom of choice to be valid, both parents should be legally competent for custody, the child should not be mentally ill, otherwise, he should be left with the mother or either of them who is qualified for custody. If the mother is religiously or physically incompetent for custody, it should be considered which among the child's relatives is more entitled to take custody of the child after her, according to the degree of kinship that preserves for the child his right of upbringing.
Charge for custody: As long as the woman who has custody receives financial maintenance during the term of ‘Iddah, she could not combine both maintenance and the charge for custody. However, when the term of the divorced woman's ‘Iddah is over and she receives no maintenance from the child's father, she then deserves charge for custody, for she performs a task in behalf of the child's father or guardian. This is in relation to the mother. But if the person who has custody is another woman, she should take charge for the services she performs. But, if she volunteers to do those services as a gift, her gift is valid, and her right of charge for custody lapses.
Conditions of custody: The woman entitled to the right of custody should have reached puberty, be of a sound mind, able to rear children, honest, well-mannered, and Muslim.