Fathwa - Permission to observe voluntary fast?

Question:
My wife is really struggling with the idea that why does a woman need
to get her husband's permission to observe voluntary fast? She is
really confused about the fact that this is an act between her and
Allah, why does she need permission from a human being? She has got
some answers from local Imams saying that the man is more inclined
towardsgoing out and committing Zina, so that's why the woman should
be readily available for her husband. This answer really made her
upset, becuase she contested that there are women out there who are as
vulnerable as men. Canyou please provide us a detailed answer, becuase
she is really struggling with this spiritually and physically.
Answer:
In the Name of Allah, the Gracious, the Merciful.
Praise be to Allah.
May Allah's peace and blessings shower upon our beloved Messenger.
Dear Brother,
I pray this message finds you and your wife in good health and spirits.
The basis for a woman's asking her husband's permission to do a
voluntary fast comes from the hadith of the Prophet, Allah bless him
and give him peace, "A woman should not fast (optional fasts) except
with her husband's permission if he is at home (staying with her)."
[Sahih Bukhari, Volume 7, Book 62, Number 120]
Our duty as Muslims is to approach the teachings of the Prophet, peace
be upon him, with the attitude enjoined by the Qur'an, "And it
becomethnot a believing man or a believing woman, when Allah and His
messenger have decided an affair (for them), that they should (after
that) claim any say in their affair; and whoso is rebellious to Allah
and His messenger, he verily goeth astray in error manifest."
[Al-Ahzab, 33:36]
The essence of Islam resides in sublimating our inclinations to what
the Messenger of Allah, peace be upon him, brought us.
Please reassure your wife that her seeking your permission to perform
a voluntary fast is neither demeaning nor degrading to her. Unlike
obligatory fasts, which are an obligation solely due to Allah Most
High, voluntary fasts involve the rights of a fellow human being,
namely the husband. Out of respect and consideration for each other,
both husband andwife should check with each other before performing a
voluntary fast.
My teacher told me that the fundamental purposes of marriage arelove,
intimacy, and companionship. It's hard to satisfy these purposes if
the spouses do not make themselves sexually available to eachother. In
Islam, marriage is a form of contract, based on the premise that the
woman will make herself sexually available to the man with his promise
that he will support her and their children. It is the wife's
religious and legalobligation to make herself available to her
husband. Likewise, it is the husband's religious and legal obligation
to satisfy his wife. Thus, they keep each other chaste.
Your wife is correct: there are some women out there who are inclined
to stray. However, generally speaking, the urge for men to stray is
usually much stronger. The rulings of Sacred Law usually address
themselves to general cases, rather than exceptions.
When a woman gets her husband's consent to perform a voluntary fast,
she can attain to much baraka (blessing) because:
1. She is following the Sunna of our Beloved Prophet, Allah bless him
and give him peace.
2. She is letting her husband know how much she cares about him.
3. She is exemplifying the noble spirit of Islamicmarriage: an
attitude of loving, compassionate concern.
4. When she exhibits such a positive attitude, Allah willing, her
husband will reciprocate.
May Allah Most High blessyou and your wife.
And Allah knows best.