Question Summary:
On what basis is a man allowed to divorce his wife?

Question Detail:

On what basis is a man allowed to divorce his wife & how should he go about it islamically.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.          
Marriage is a very special bond between a husband and wife based on love, harmony and unity. If a marriage is maintained correctly with all its etiquettes then the marriage will be a source of peace, happiness and serenity. If the husband and wife fail to fulfil one another’s rights, the marriage can evolve into a burden and at times, into divorce.
In view of the importance of marriage and in view of the rights of one another, it is imperative that efforts should be made to maintain the marriage at all times in one’s life. If a dispute arises between the husband and the wife and living together becomes difficult, in such a situation one should not resort to divorce immediately, in spite of even major differences between the spouses. All efforts should be made for reconciliation between the spouses. Consider the following verse,
وَاللَّاتِي تَخَافُونَ نُشُوزَهُنَّ فَعِظُوهُنَّ وَاهْجُرُوهُنَّ فِي الْمَضَاجِعِ وَاضْرِبُوهُنَّ فَإِنْ أَطَعْنَكُمْ فَلَا تَبْغُوا عَلَيْهِنَّ سَبِيلًا إِنَّ اللَّهَ كَانَ عَلِيًّا كَبِيرًا . وَإِنْ خِفْتُمْ شِقَاقَ بَيْنِهِمَا فَابْعَثُوا حَكَمًا مِنْ أَهْلِهِ وَحَكَمًا مِنْ أَهْلِهَا إِنْ يُرِيدَا إِصْلَاحًا يُوَفِّقِ اللَّهُ بَيْنَهُمَا إِنَّ اللَّهَ كَانَ عَلِيمًا خَبِيرًا
Translation: As for those (wives) whose disobedience you fear, advise them: (if this fails, then) separate your bed from theirs (within the same house) and (in extreme circumstances) hit them (gently, without injuring them, without striking the face and without leaving any marks on the body). If they obey you, then do not look for a way against them (do not look for an excuse to oppress them or to wrongfully accuse them). Verily Allah is Most High, The Greatest. [34] If you fear that the couple may separate, then appoint (with their consent) a mediator from his family and a mediator from her family (because relatives generally have a mere thorough knowledge of the situation). If they (the mediators) both desire reconciliation, Allah will create unity between the couple (if this is best for them). Verily Allah is All Knowing, Informed. (He knows what is best for all and He knows what methods are best to resolve disputes.) [4: 34-35] 
As far as possible, one should avoid issuing a divorce. Divorce is the most detested permissible act in Shariah. Consider the following Hadith:
عَنِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ :أَبْغَضُ الْحَلَالِ إِلَى اللَّهِ تَعَالَى الطَّلَاقُ
Translation: The most disliked permissible act in the eyes of Allah is divorce [[i]]
 
However, if all attempts were made in saving the marriage and that was unsuccessful, then at such instances breaking off the marriage may be the best of options for the couple. Therefore the husband may issue a divorce. The most preferable method of issuing a divorce is as follows:
To give one Talaaq e Rajie (revocable divorce) in such a tuhur (state of purity) where there was no intercourse.[[ii]] Talaaq e Rajie is a type of divorce wherein the husband divorces his wife in explicit terms. For example, he says “I divorce you”, or “You are divorced”.[[iii]] 
Once the husband utters such type of words, the wife becomes divorced and she has to sit in Iddah (waiting period) for three menstrual cycles if she experiences menses, or three months if she does not experience menses or child birth if she has conceived.
If the husband wishes to take her back, he may do so during the Iddah period. The husband may verbally take her back, for example he says to her “I take you back” etc., or by being physical with her, for example kissing her or having intercourse with her.[[iv]]
If the husband does not take her back as explained above during the Iddah period, the divorce becomes an irrevocable divorce. Therefore, if he wishes to take her back (after the Iddah period has finished), he can only do so after renewing the Nikah. [[v]]
 
 
And Allah Ta’āla Knows Best 
Fahad Abdul Wahab
Student Darul Iftaa
U.S.A 
Checked and Approved by,
Mufti Ebrahim Desai.