Praise be to Allah.
The husband is obliged to treat his wife in a kind and reasonable manner. Part of that kind and reasonable treatment is intercourse, which he has to do. The majority of scholars set the time limit beyond which it is not permissible for the husband to forego intercourse at four months, but the correct view is that there is no time limit; the husband should have intercourse with his wife according to what satisfies her.
Ibn Qudaamah (may Allaah have mercy on him) said:
Intercourse is obligatory upon the man if he has no excuse. This was also the view of Maalik.
He (the husband) is obliged to have intercourse with her, because Allaah says (interpretation of the meaning):
“…so as to leave the other hanging (i.e. neither divorced nor married)…”
meaning, neither divorcing her so that she can marry another or leaving her without a husband because he is not fulfilling his duty of having intercourse with her.
Ahkaam al-Qur’aan, 1/374
Shaykh al-Islam (may Allaah have mercy on him) said:
It is obligatory upon the husband to have intercourse with his wife according to what will satisfy her, so long as this will not harm him physically, or keep him from earning a living, and that is not restricted to four months.
Al-Ikhtiyaaraat al-Fiqhiyyah, p. 246.
It is obligatory for the wife to obey her husband if he calls her to his bed. If she refuses she is sinning.
It was narrated from Abu Hurayrah (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said: “If a man calls his wife to his bed, and she refuses to come, the angels curse her until morning comes.”
Narrated by al-Bukhaari, 3065; Muslim, 1436.
Shaykh al-Islam [Ibn Taymiyah] said:
She must obey him if he asks her to come to his bed, and that is obligatory upon her. If she refuses to come to his bed, she is a defiant sinner… as Allaah says (interpretation of the meaning):
“As to those women on whose part you see ill-conduct, admonish them (first), (next) refuse to share their beds, (and last) beat them (lightly, if it is useful); but if they return to obedience, seek not against them means (of annoyance)”
al-Fataawa al-Islamiyyah, 3/145, 146
It is not permissible for a husband to force his wife to do more than she is able to bear of intercourse. If she has an excuse such as being sick or unable to bear it, then she is not sinning if she refuses to have intercourse.
Ibn Hazm said:
It is obligatory on slave women and free women alike not to refuse their masters or husbands if they call them, so long as the woman who is called is not menstruating or sick in such a way that intercourse will be harmful to her, or observing an obligatory fast. If she refuses with no excuse, then she is cursed.
The husband has the right to enjoy intimacy with his wife at any time… so long as he does not distract her from obligatory religious duties or harm her. In that case he does not have the right to intimacy with her without her permission, because that is contrary to the idea of reasonable and kind treatment. So long as he does not distract her from that and does not harm her, then he has the right to intimacy.
Kashf al-Qinaa’, 5/189
The wife whose husband harms her by having intercourse with her too much can agree with her husband the number of times that she can bear. If he does more than that to the point that he harms her, she can refer the matter to the qaadi (judge), and the qaadi can determine the number of times that the husband and wife should stick to.
Shaykh al-Islam Ibn Taymiyah said:
The husband should have intercourse with his wife according to what satisfies her, so long as that does not harm him physically or keep him from earning a living; it is not limited to four months.
If they argue, then the judge should decide on the number of times, just as the judge should decide on the level of spending on a wife.
Al-Ikhtiyaaraat al-Fiqhiyyah, p. 246
Because there are no sharee’ah courts nowadays in your country, the wife should try to come to an agreement with her husband on this matter, so she should speak to him frankly and remind him of the verses and ahaadeeth that command the husband to be kind to his wife. She should explain to him that she is only refusing because of the harm that is being caused to her, and that she is very keen to obey him and respond to his desires. Our advice to the sister is that she should be patient with her husband and put up with it as much as she can, and she should note that she will be rewarded for that by Allaah.
The husband has to fear Allaah with regard to his wife, and not make her do more than she is able to do. He should be kind to his wife and treat her in a reasonable manner. If his desire is so strong that one wife is not enough for him, then why does he not try to look for a solution to this problem that is affecting his relationship with his wife, or which may lead to something even worse, which would be looking to satisfy his desire in haraam ways?
One of the solutions that would help to solve this problem is to take a second wife. Allaah has permitted men to marry up to four, on condition that he treat them all fairly. Another solution would be to fast a lot, because fasting reduces desire. And another solution would be to take medicine that will reduce his desire, subject to the condition that this will not cause him any harm.
And Allaah is the One Whom we ask to set the Muslims’ affairs straight.
And Allaah knows best.