The Expenses of Hajj:
The husband is not obliged to pay the expenses of Hajj for his wife unless this is stipulated in the marriage contract.
His eminence Shaykh Ibn Baaz was asked, "Is the husband obliged to pay the expenses of Hajj for his wife?"
He answered, "The husband is not obliged to pay the expenses of Hajj for his wife; rather, she should pay the expenses if she is capable for Allah The Almighty Says (what means): {…And [due] to Allah from the people is a pilgrimage to the House - for whoever is able to find thereto a way….} [Quran 3:97] It was also narrated on the authority of ‘Umar Ibn Al-Khattaab that when Jibreel asked the Prophet about Islam, he answered: “Islam is to testify that there is none worthy of worship except Allah and that Muhammad is the Messenger of Allah, to perform prayer, to pay Zakah [obligatory charity], to fast in Ramadan and to perform Hajj to the House if you are able to find thereto a way." [Muslim] This noble verse and honored Hadeeth encompass both men and women as well as married and unmarried women. However, if he volunteers to pay for her then this is appreciated and rewarded, and Allah is the Bestower of success."
His eminence Shaykh Ibn ‘Uthaymeen was asked, "Is a man obliged to perform Hajj with his wife as her Mahram? Is he required to spend on his wife during Hajj?"
He answered, "The husband is not obliged to perform Hajj with his wife unless this was set as a condition when concluding the marriage, in which case he should fulfill the condition. He is not required to spend on his wife except if it is the obligatory Hajj which he permitted her to perform, in which case he should spend on her only as much as he would do in their country of residence."
This has a great reward. It is also a reason for affinity between the spouses and it falls under kind treatment.
Spending on the Wife:
Spending on the wife is obligatory upon the husband, and it is also obligatory upon the husband to spend on his wife during Hajj.
Scholars stated that the husband should spend on his wife during her obligatory Hajj.
However, it is not obligatory upon him to spend on her in voluntary Hajj even if she goes with his permission.
Concerning a vowed Hajj, the scholars have mentioned that if the vow was made before the marriage, then she is entitled to maintenance because it became obligatory before marriage and thus it takes precedence over the husband's right over her. If it was made after marriage with the permission of the husband, she is also entitled to maintenance because he allowed her to assume this obligation and is satisfied with what it entails.
If it was without his permission, then she is not entitled to maintenance because she deprived her husband of his right to have intercourse with her willingly on her part and without his consent. This would resemble traveling for her private purposes that have nothing to do with her husband.
If the husband and wife are making up for Hajj due to violating Ihraam (ritual consecration) by having intercourse (in a previous Hajj), then wife is obliged to pay for herself if she responded but if she was forced then the husband is obliged to pay.
Maintenance of the Mahram:
The woman is obliged to spend on her Mahram during Hajj (brought specifically for enabling her to fulfill her duty) because having a Mahram is one of the conditions that make her capable of performing Hajj; so she should spend on him – even if her Mahram is her husband. If the Mahram abstains in spite of being offered maintenance, then she is just like those who have no Mahram; thus, she is not obliged to perform Hajj.
The Mahram of a Woman in Hajj:
Having a Mahram is among the conditions that make Hajj obligatory upon a woman. She may not travel without him. The Prophet said: "A woman must not travel for more than three days except with a Mahram." [Al-Bukhari and Muslim] Ibn ‘Abbaas narrated that he heard the Prophet saying: "It is not permissible for a man to be alone with a woman without there being a Mahram present, and no woman should travel except with a Mahram." A man then got up and said, "O Messenger of Allah, I have enlisted in the army for such-and-such a Ghazwah (battle) and my wife is proceeding for Hajj." The Messenger of Allah said, "Go and perform Hajj with your wife." [Al-Bukhari and Muslim]
A Mahram is her husband or a person whom she cannot marry in any case permanently because of a relation of kinship or a certain reason. He must be an adult and in full possession of his mental faculties. This is because the Mahram is meant to protect the woman and this cannot be achieved except by an adult who is in full possession of his mental faculties. If her Mahram dies while they are traveling, she may proceed, especially if they have traveled a long distance and it is an obligatory Hajj. Concerning the voluntary Hajj, some scholars have mentioned the opinion that she should return or remain in the country where her Mahram died.