Polygyny in Islam
Question

I was really into becoming a Muslim. I came to this site to find out how to become Muslim. On doing so, I found out a lot about the religion I never knew before, and it’s kind of disturbing and almost a letdown. I’m sorry I feel like that but it’s true.
One of the things that bothers me is the polygamy thing, I would like to know where it addresses that in the Quran. Please try to give me tips on how to live like that and remain sane.
Praise be to Allah.Allah will not accept any religion other than Islam
Allah concluded His Message to mankind with the religion of Islam, and He tells us that He will not accept any religion other than that. Allah says (interpretation of the meaning):
“And whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be one of the losers.” [Aal ‘Imran 3:85]
Your backing away from the religion of Islam is considered to be a loss for you, and a loss of the happiness that awaited you, had you entered Islam. You should hasten to enter Islam, and beware of delaying, for that delay may lead to regrettable consequences.
With regard to what you mention about the reason for your backing off being the idea of plural marriage [polygamy or polygyny], we will present to you the ruling on plural marriage in Islam, and then the wisdom and noble purposes behind it.
Ruling on polyguny in Islam
The shar’i text which permits plural marriage is:
Allah says in His Noble Book (interpretation of the meaning):
“And if you fear that you shall not be able to deal justly with the orphan girls then marry (other) women of your choice, two or three, or four; but if you fear that you shall not be able to deal justly (with them), then only one or (slaves) that your right hands possess. That is nearer to prevent you from doing injustice.” [al-Nisa 4:3]
This is a Quranic text which shows that plural marriage is allowed. According to Islamic shari’ah, a man is permitted to marry one, two, three or four wives , in the sense that he may have this number of wives at one time.
It is not permissible for him to have more than four. This was stated by the commentators on the Quran and jurists, and there is consensus among the Muslims on this point, with no differing opinions.
Conditions of polygyny in Islam
It should be noted that there are conditions attached to plural marriage :

Justice or fairness

Allah says (interpretation of the meaning):
“but if you fear that you shall not be able to deal justly (with them), then only one.” [al-Nisa 4:3]
This verse indicates that just treatment is a condition for plural marriage to be permitted.
If a man is afraid that he will not be able to treat his wives justly if he marries more than one, then it is forbidden for him to marry more than one.
What is meant by the justice that is required in order for a man to be permitted to have more than one wife is that he should treat his wives equally in terms of spending, clothing, spending the night with them and other material things that are under his control.
With regard to justice or fairness in terms of love, he is not held accountable for that, and that is not required of him because he has no control over that. This is what is meant by the verse,
“You will never be able to do perfect justice between wives even if it is your ardent desire.” [al-Nisa 4:129 – interpretation of the meaning]

The ability to spend on one’s wives

The evidence for this condition is the verse:
“And let those who find not the financial means for marriage keep themselves chaste, until Allah enriches them of His Bounty.” [al-Nur 24:33 – interpretation of the meaning]
In this verse, Allah commands those who are able to get married but cannot find the financial means, to remain chaste. One such example is not having enough money to pay the mahr (dowry) and not being able to spend on one’s wife. (al-Mufassal fi Ahkam al-Marah, part 6, p. 286).
Why is polygyny permissible in Islam?

Plural marriage helps to increase the numbers of the ummah (nation, Muslim community). It is known that the numbers can only be increased through marriage, and the number of offspring gained through plural marriage will be greater than that achieved through marriage to one wife.

Wise people know that increasing the number of offspring will strengthen the ummah and increase the number of workers in it, which will raise its economic standard – if the leaders run the affairs of the state well and make use of its resources in a proper manner. Ignore the claims of those who say that increasing the numbers of human beings poses a danger to the earth’s resources which are insufficient, for Allah (the Most Wise Who) has prescribed plural marriage has guaranteed to provide provision for His slaves and has created on earth what is more than sufficient for them.
Whatever shortfall exists is due to the injustice of administrations, governments and individuals, and due to bad management. Look at China, for example, the greatest nation on earth as far as number of inhabitants is concerned, and it is regarded as one of the strongest nations in the world, and other nations would think twice before upsetting China; it is also one of the great industrialized nations. Who would dare think of attacking China, I wonder? And why?

Statistics show that the number of women is greater than the number of men; if each man were to marry just one woman, this would mean that some women would be left without a husband, which would have a harmful effect on her and on society:

The harmful effect is that she would never find a husband to take care of her interests, to give her a place to live, to spend on her, to protect her from haram desires, and to give her children to bring her joy. This may lead to deviance and going astray, except for those on whom Allah has mercy.
With regard to the harmful effects on society, it is well known that this woman who is left without a husband may deviate from the straight path and follow the ways of promiscuity, so she may fall into the swamp of adultery and prostitution – may Allah keep us safe and sound – which leads to the spread of immorality and the emergence of fatal diseases such as AIDS and other contagious diseases for which there is no cure. It also leads to family breakdown and the birth of children whose identity is unknown, and who do not know who their fathers are.
Those children do not find anyone to show compassion towards them or any mature man to raise them properly. When they go out into the world and find out the truth, that they are illegitimate, that is reflected in their behaviour, and they become exposed to deviance and going astray. They may even bear grudges against society, and who knows? They may become the means of their country’s destruction, leaders of deviant gangs, as is the case in many nations in the world.

Men are exposed to incidents that may end their lives, for they work in dangerous professions. They are the soldiers who fight in battle, and more men may die than women. This is one of the things that raise the percentage of husbandless women, and the only solution to this problem is plural marriage.
There are some men who may have strong physical desires, for whom one wife is not enough. If the door is closed to such a man and he is told, you are not allowed more than one wife, this will cause great hardship to him, and his desire may find outlets in forbidden ways.

In addition to that, a woman menstruates each month, and when she gives birth, she bleeds for forty days (this post-partum bleeding is called nifas in Arabic), at which time a man cannot have intercourse with his wife, because intercourse at the time of menstruation or nifas is forbidden, and the harm that it causes has been proven medically. So plural marriage is permitted when one is able to be fair and just.

Plural marriage does not exist only in the Islamic religion, rather it was known among the previous nations. Some of the prophets were married to more than one woman. The Prophet of Allah Sulayman (Solomon) had ninety wives. At the time of the Prophet (peace and blessings of Allah be upon him), there were some men who became Muslims who had eight or five wives. The Prophet (peace and blessings of Allah be upon him) told them to keep four wives and to divorce the rest.
A wife may be barren, or she may not meet her husband’s needs, or he may be unable to have intercourse with her because she is sick. A husband may long to have children, which is a legitimate desire, and he may want to have a sex life within marriage, which is something permissible, and the only way is to marry another wife. It is only fair for the wife to agree to remain his wife and to allow him to marry another.
A woman may be one of the man’s relatives and have no one to look after her, and she is unmarried or a widow whose husband has died, and the man may think that the best thing to do for her is to include her in his household as a wife along with his first wife, so that he will both keep her chaste and spend on her. This is better for her than leaving her alone and being content only to spend on her.
There are other shar’i interests that call for plural marriages, such as strengthening the bonds between families, or strengthening the bonds between a leader and some of his people or group, and he may think that one of the ways of achieving this aim is to become related to them through marriage, even if that is through plural marriage.

Objections to polygyny in Islam
1. Some people may object and say that plural marriage means having co-wives in one house, and that the disputes and enmity that may arise between co-wives will have an effect on the husband, children and others, and this is harmful and should be avoided, and the only way to prevent that is to ban plural marriage.
The response to this objection is that family arguments may occur even when there is only one wife, and they may not even happen when there is more than one wife, as we see in real life. Even if we assume that there may be more arguments than in a marriage to one wife, even if we accept that they may be harmful and bad, the harm is outweighed by the many good things in a plural marriage. Life is not entirely bad or entirely good, but what everyone hopes is that the good will outweigh the bad, and this principle is what applies in the permission for plural marriage.
Moreover, each wife has the right to her own, separate accommodation as prescribed in Islam. It is not permissible for the husband to force his wives to live together in one house.
2. If we allow men to have plural wives, why are women not allowed to have multiple husbands , why does a woman not have the right to marry more than one man?
The response to this objection is that there is no point in giving a woman the right to marry multiple husbands, rather that is beneath her dignity and she would not know the lineage of her children, because she is the one who bears the offspring, and it is not permissible for the offspring to be formed from the sperm of a number of men lest the lineage of the child be lost and no one will know who is responsible for bringing up the child; this will lead to breakdown of families, loss of ties between fathers and children, which is not permitted in Islam as it is not in the interests of the woman or of the child or of society as a whole.
Reference:
Al-Mufassal fi Ahkam al-Marah, part 6, p. 290.
And Allah knows best.