Praise be to Allah.
It is not permissible for a husband to question his wife about the mahr which he gave to her, because this is her right and a debt on him which he has to give to her.
In return for this small amount of money which Allaah has granted to the woman, the right of qiwaamah (being in charge, being the protector and maintainer) is taken from her and given to her husband. So his spending on her is in return for something very precious and the mahr and spending on her is in return for that qiwaamah. Allaah says (interpretation of the meaning):
“Men are the protectors and maintainers of women, because Allaah has made one of them to excel the other, and because they spend (to support them) from their means”
Imam al-Tabari (may Allaah have mercy on him) said:
“Men are the ones who are in charge of their womenfolk, disciplining them and making them fulfil their obligations towards Allaah and towards themselves. ‘Because Allaah has made one of them to excel the other’ means, because Allaah has given men an advantage over their wives because of the mahr which they give to them, and because they spend on them from their own money, and they take care of them. This is the way in which Allaah has caused them to excel them. Hence they are in charge of them and women are expected to obey their husbands.
Tafseer al-Tabari, 5/57
So the mahr is the woman’s right, just as qiwaamah is the man’s right. Just as she should not disobey him because of that qiwaamah, so he should give her her rights.
Men must fear Allaah with regard to their wives’ mahr and give them their mahrs. For women are weak, so men should give them their rights.
Allaah says (interpretation of the meaning):
“O you who believe! Fulfil (your) obligations”
And indeed the marriage contract is one of the most important contracts which the Muslims are obliged to fulfil.
It was narrated that ‘Uqbah ibn ‘Aamir (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “The conditions which most deserve to be fulfilled are those by means of which intimacy becomes permissible to you.”
(Narrated by al-Bukhaari, 2520; Muslim, 2542)
So long as a woman has taken possession of this money in this manner, her husband has no right to force her to spend it in a particular way, unless she is spending it on something haraam, in which case he has the right to stop her from spending it in haraam ways.
Our advice to you is to deal with your husband gently and calmly when he questions you about the mahr, lest a dispute concerning this matter be the cause of letting the Shaytaan come between you, especially when you are at the beginning of your married life, which should be based on harmony and tolerance on both sides towards any shortcomings or transgressions on the other side. We ask Allaah to decree for you a happy life filled with obedience to Allaah and following his laws. And Allaah knows best.