Islam – being a natural way of life – takes into account all of genuine human instincts such as physical, spiritual, intellectual, emotional, et cetera. Islam generally encourages marriage as the pure and legitimate way for regulating and fulfilling these instincts and desires. It is against both curbing man’s desires through celibacy or giving them free rein through licentiousness and sexual permissiveness.
the ruling on marriage differs according to the state and conditions of each person. It can be obligatory or recommendable under certain conditions. It can also be prohibited or only permitted under other circumstances. The different rulings on marriage are explained in the fatwa issued by the late prominent Muslim scholar and author of Fiqh As-Sunnah, Sheikh Sayyed Sabiq. He states the following:

“Obligatory Marriage:
Marriage is obligatory for whoever is able to afford it, has desire for sexual intercourse, and is afraid to indulge in fornication. Here, it is obligatory because protecting oneself against fornication and preserving one’s chastity is obligatory, and this cannot be achieved except through marriage. Al-Qurtubi says: “Celibacy is not recommended for whoever is able to bear the expenses of marriage, and is likely to commit illicit affairs that violate both his honor and his religion, for one sometimes may not be able to overcome temptation except by marriage. In this case marriage is, according to a scholarly consensus, obligatory. But one who has desire for sexual intercourse, but does not have enough money for the expenditures of marital life may find solace in the words of Allah, Exalted be He, Who says: “Let those who find not the wherewithal for marriage keep themselves chaste, until Allah gives them means out of His Grace.” (An-Nur: 33)

Man is recommended to suppress his sexual appetite by fasting; a group of Hadith transmitters narrated on the authority of Ibn Mas`ud (may Allah be pleased with him) that Allah’s Messenger (peace and blessings be upon him) said: “O youth! Whoever amongst you is able to marry, let him marry, because it helps him keep his eyes away from lustful looks and preserve his chastity. And whoever is not able to marry, let him observe fasting, as it is a shield for him (i.e. protection from lapsing in fornication).”

Commendable Marriage:
One who has desire for sexual intercourse, who is able to bear the expenses of marriage, and, at the same time, is able to suppress his sexual desire, protect himself against committing illicit affairs is recommended to marry. In this case, marriage in this case is better than devoting oneself to worship, because monasticism is not a characteristic of Islam. At-Tabarani narrated on the authority of Sa`d ibn Abi Waqqas that Allah’s Messenger (peace and blessings be upon him) said: “Allah has revealed tolerant monotheism (Islam), to replace the Christians’ monasticism.” Al-Bayhaqi also narrated on the authority of Abu Umamah that the Prophet (peace and blessings be upon him) said: “Marry one another, for I will be boast of your great numbers in front of other nations (on the Day of Judgement), but don not lapse in the Christians’ monasticism.” `Umar once said to Abu Az-Zawa’id: “Nothing can make man refrain from marriage except inability or indulging in fornication.” Ibn `Abbas also said: “The faith of a devoted believer will never be perfected unless he marries.”

Prohibited Marriage:
Marriage is prohibited for anyone who cannot observe his wife’s rights, because of being undesirous for sexual intercourse due to a physical defect, or because of inability to afford marriage. Al-Qurtubi states: When man is unable to marry due to lack of money to cover the expenses of marriage, to pay the bride’s dowry, or any of her financial rights, he must not marry unless he lets the bride know of his inability, or unless he becomes able to afford marriage. And so is the case if he has some physical weakness that makes him unable to have sexual intercourse (i.e. if he is impotent); he must let his bride know of it, in order not to deceive her. Moreover, he must not pretend that he hails from a noble family, that he is a wealthy man, or that he holds a prestigious post.
the same applies to women. A woman who is unable to observe her husband’s rights, or who has some defect which prevents her husband from making love to her, such as insanity, leprosy, elephantiasis, genital or vaginal disease, must never deceive him; rather, she must let him know what is wrong with her. This is like the example of a sale contract; the seller must inform the buyer of any defect in the commodity he is purchasing.
that is to say, when one of the spouses finds some defect in his/or her mate, he/or she may annul the marriage. Thus, when the husband finds any defect in his wife, he may annul the marriage, and take back the dowry he paid her. It was narrated that the Prophet (peace and blessings be upon him) married a woman from Bayadah folk. Then he found that she was leprous in her flank, so he sent her back to her parents, and said to them. “You have deceived me.”
Imam Malik is reported to have stated two different opinions concerning the wife of the impotent, who discovers this after consummating marriage then seeks separation on account of this defect. Imam Malik once said that in such a case the wife can seek for marriage annulment and take her full dowry; his another view is that she takes half of her dowry. By and Large, Malik’s different points of view depend on his different opinions as to whether the bride’s dowry is due immediately after she allows her husband to have sex with her, or after he consummating marriage.

Permissible Marriage:
Marriage is permissible for any person who has nothing to warrant his marriage or prohibit it.”