The separation between the Spouses is done by either Talaaq (Divorce) of Faskh(annulment).
Talaaq means the ending the marital relationship by the Husband i.e. the relationship is instigated by Husband and it involves specific well-known phrases.
Faskh is the annulment of the marriage contract and the marital bond is dissoluted completely as if it never happened. It can only be done by means of Qaazi(Judge).
The differences between the two include the following:
1. Talaaq requires the utterance of words and phrases of such by the husband, with his consent and his choice whereas Faskh is not uttered by husband and is not conditional upon his consent or choice.
Imam ash-Shaafa‘i (may Allah have mercy on him) said: Any case in which it is ruled [by a qaazi] that a couple be separated, when the husband did not utter words to that effect and did not want it… this is a separation and be called talaaq. End quote. Al-Umm (5/128).
2. Talaaq can be done on many reasons and it may occur for a reason that the husband wants to leave his wife.
3. Faskh can only occur when there is a reason that makes it necessary or permissible.
Examples of reasons for which the marriage contract may be annulled (faskh) include the following:
· Lack of compatibility between spouses.
· If one of the spouses gets away from Islam and does not come back.
· If the husband becomes Muslim while Wife continues to be a polytheist and is not among the people of the book.
· When Li’aan occurs between the spouses. [li‘aan is a process done where the husband accuses the wife of adultery and she denies it, and each swears oaths invoking the curse of Allah if he or she is lying].
· Presence of defect between the spouses that prevents intimacy or creates revulsion among them.
4. The husband has no right to take his wife back after faskh (annulment). He can only take her back with a new marriage contract and with her consent. In the case of talaaq, she is still his wife so long as she is still in ‘iddah following a revocable talaaq (i.e., first or second talaaq), and he has the right to take her back after the first or second talaaq, without a new marriage contract, and regardless of whether she agrees or not.
5. Faskh is not counted as one of the three talaaqs but a complete separation.
Imam ash-Shaafa‘i said: Any faskh that occurs between the spouses is not counted as a talaaq, whether a first or subsequent talaaq. End quote from al-Umm (5/199).
Ibn ‘Abd al-Barr said: The difference between faskh and talaaq, even though each of them is a separation between the spouses, is that if the spouses get back together after faskh, then they will get back together on the basis of the original marriage and the woman still has three talaaqs left with her husband, whereas if he divorced her by talaaq then took her back, she has two talaaqs left with him. End quote from al-Istidhkaar (6/181).
Ibn al-Qayyim said: The spouses do not have the right to agree to annul the marriage without compensation (i.e., khul‘), according to scholarly consensus. End quote from Zaad al-Ma‘aad (5/598).
6. If faskh occurs before consummation of the marriage, the woman is not entitled to anything of the mahr (dowry). In the event of talaaq before consummation of the marriage, she is entitled to half of the agreed-upon mahr.
As for khul‘, this refers to when the woman asks her husband to separate from her in return for financial compensation or giving up her mahr or part of it.
And Allah knows best.