(Explanation in the light of Surah an-Nisa Ayah 24)
وَالْمُحْصَنَـتُ مِنَ النِّسَآءِ The women already bound in marriage: It means that women having husbands have also been made unlawful. So far as a woman is married to a person, no other person can marry her. From here, it becomes very clear that a woman cannot live with more than one husband simultaneously. There are some ignorant and loud-mouthed people in our time who have started saying – when men are allowed to take more than one wife, women too should have the permission to enjoy more than one husband. This tasteless bravado is totally contrary to this ayah. People who indulge in such flippant display of ignorance do not see that plurality of wives is a blessing which has been historically endorsed in all religions and societies. But, for a woman, having more than one husband at the same time is not only a headache for her in person, but it is also disgraceful for those two men who become husbands to one woman. This weird arrangement is not only shameless, but also leaves no possibility of any offspring being born lineally sound.
When many men benefit from one woman, there will remain no method of attributing the fatherhood of the child so born to any one of the participating husbands. Such an obnoxious demand can only be made by those who are totally hostile to the graces of humanity, those who have buried their sense of shame once and for all and those who are supporting the movement to deprive human beings of blessings that issue forth from the recognized channel of parents and children bound in a charter of mutual rights. When lineage goes unproved, who is going to be charged with the responsibility of taking care of mutual rights and duties?
Even if this is looked at purely in terms of nature and reason, there seems to be no justification for the provision of several husbands for one woman:
The basic purpose of marriage is procreation. Seen from this angle, several women can certainly become pregnant from one man, but one woman cannot become pregnant from several men. She will become pregnant from none but one. What has thus happened is that, given the presence of several husbands, the procreating ability of all husbands, except one, was totally wasted on that count. They ended up with nothing beneficial except the lone satisfaction of their sexual drive.
Experience shows that woman is a genre more delicate than man. For a major portion of the year, she does not remain physically amenable to intimacy. There are conditions and circumstances in married life when it is not possible for her to fulfill the rights of even one husband, let alone more than one husband seeking her physical attention.
Since man is healthier and stronger in terms of physical power as compared to woman, man should, if his sexual strength is above average and he cannot find satisfaction by limiting himself to one woman, have the opportunity, of course by permissible means, to marry twice and thrice. If this is not allowed, he will take to impermissible ways of satisfying his desires, and in that process, he will ruin the whole society. But the likelihood that woman could bring about such ruination is very remote.
This question is so important in the Shariah that it has not only ruled the second marriage of a woman unlawful when she is already married to someone else, but it also goes farther when it rules that, should the husband of a woman divorce her, or die, she still cannot marry another person until after the expiry of her iddah or waiting period.
(Taken from Maaruf-ul-Qur’an by Mufti Muhammad Shafi Usmani)