Answer
Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Islam highly urges all spouses to satisfy each other’s desires, as that is one of the main objectives of marriage in Islam.
2- However, these matters should be softly and gently dealt with; namely, each spouse sometimes should forgive his/her partner for being neglectful or tired.
Responding to your question, Dr. Muhammad Salama, PhD in Islamic Studies in English and an Associate Professor at the Faculty of Islamic Science, Al-Madinah International University, states:
One of the major objectives of marriage is to satisfy the sexual desire of the spouses in a lawful way. Therefore, a husband has to satisfy the desire of his wife as the Almighty Allah said, “For women, there are [rights] equal to what is enjoined upon them, in accordance with what is right.” (Al-Baqrah 2:228)
But a husband does not have to answer her need every time she asks for that, because he may be tired or busy or have any other excuse. There is no specific number for the times that a husband has to sleep with his wife. Some women have stronger sex drive than their husbands and this may cause a woman to have troubles as mentioned in the question. This is often due to the plenty of leisure time a woman has.
I advise such a woman to be patient and try to keep herself busy with useful activities. When one is busy, sometimes he/she even forgets to eat. She may also practice fasting to control her mood.
The husband is also advised to be polite when offering his excuse for not having intercourse at a specific time and to try to contain the feelings of his wife and to compensate his wife by offering gifts and showing good attitude towards her.
Allah Almighty knows best.