First of all, it is to be stated that “Islam provides a system, which regulates family life as well as the life of the community as a whole. In every respect of its legislation and in its regulation of relations between various groups and individuals in society, Islam maintains justice, fair treatment and a balance between rights and responsibilities. In this way it provides a solid basis for a strong, closely knit community.
Because the woman is the weaker partner in the family relationship, Islam places strong emphasis on the importance of being fair to women, and not to abuse them in any way. The Prophet (peace and blessings be upon him) describes those who are kind and good to their wives as the best of people. He (peace and blessings be upon him) is reported to have said: “The best among you are those who are best to your households; I am the best among you to my house-hold.”

On his deathbed, the Prophet (peace and blessings be upon him) continued to remind the followers of three areas as needing continuous attention. The first concerns man’s relationship with Allah while the other two are concerned with human relations, concentrating on the need to protect the rights of two vulnerable groups in society, namely, women and slaves. He said repeatedly: “Attend to your prayers. Do not ask those whom your right hands possess to accomplish for you what they cannot do. Fear Allah in your treatment of women.”
Sheik Yusuf Al-Qaradawi, in his well-known book, The Lawful and the Prohibited in Islam. He writes: “The condition which Islam lays down for permitting a man to have more than one wife is confidence on his part that he will be able to deal equitably with his two or more wives in the matter of food, drink, housing, clothing and expenses, as well as in the division of his time between them. Anyone who lacks the assurance that he will be able to fulfill all these obligations with justice and equality is prohibited by Allah Almighty from marrying more than one woman, for Allah says:”But if you fear that you will not be able to do justice (among them), then (marry) only one…” (An-Nisa’: 3)
And the Prophet (peace and blessings be upon him) said, “Anyone who has two wives and does not treat them equally will come on the Day of Resurrection dragging one part of his body which will be hanging down.” (Reported by the compilers of Sunan and by Ibn Hibban and al-Hakim)
The equal treatment mentioned here pertains to the rights of the wives, not to the love the husband feels towed them, for equality in the division of love is beyond human capacity and any imbalance in this regard is forgiven by Allah Almighty who says: “And you will not be able to do justice among (your) wives, however much you may wish to. But do not turn away (from one of them) altogether…” (An-Nisa’: 139)
This is why the Prophet (peace and blessings be upon him) used to divide his time among his wives equally, saying, “O Allah, this is my division in regard to what I can control. Then do not take me to task regarding what Thou controllest and I do not control” (Reported by the compilers of Sunan), referring to the attachment and affection which he felt for one particular wife. And when he planned to go on a journey, Allah’s Messenger (peace and blessings be upon him) would cast lots among his wives, and the one who was chosen by lot would accompany him. (Reported by al-Bukhari and Muslim)
In conclusion, we would like to advise every husband to fear Allah and to be just in dealing with their wives, in order to be spared of Allah’s Punishment on the Day of Resurrection. He can simply attain such justice if he fears Allah and seeks His Guidance. Still, the issue requires mutual understanding between families. With your concerted efforts, you will live in harmony, even if he is married to a second wife!