Short answer
She can ask, but in the Hanafi school a condition like "he will not marry again" does not legally bind him, though he should keep his word. What does bind is giving her the right to divorce herself (tafwid al-talaq) if he marries again or breaks another term. The Hanbali school makes such conditions binding.
Conditions that restrict what the Shariah allows the husband, such as not taking a second wife or not moving her from her city, do not bind him legally: the nikah is valid and the condition void, though keeping a promise is a moral duty. A delegated right of divorce (tafwid) tied to a condition is valid and binding, so she may divorce herself if the condition is broken.
Other madhhabs
- Hanbali
- Conditions that benefit the wife, such as not marrying another woman or not moving her from her home town, are binding. If he breaks one, she may annul the marriage.
- Shafi'i
- Such conditions are void, as in the Hanafi school, while the nikah itself stands.
Explanation
The Prophet ﷺ said that the conditions most deserving to be fulfilled are those by which marriage is made lawful. He also said Muslims are bound by their conditions, except a condition that makes the haram halal or the halal haram. The schools read these two hadith differently, which is why they differ here.
The Hanafis say the conditions that must be kept are the ones the nikah already requires: mahr, maintenance, good treatment. A condition that takes away something Allah allowed him, like a second marriage, is not binding in law. Still, a believer keeps his promises (5:1), and breaking his word to his wife is blameworthy.
The Hanafi way to protect her: tafwid al-talaq. The husband gives the wife the right to pronounce a talaq on herself in set situations. This is binding. Clauses scholars often suggest:
- If he marries another wife without her written consent.
- If he fails to provide maintenance for a set number of months.
- If he harms her physically or leaves her for more than a set period.
The wording matters: the number and type of talaq, and whether the right lasts or ends after one use. Have a mufti draft or check it, and write it into the nikah certificate.
Many couples in the West also sign a civil agreement. That can protect money and property under the law of the land, but it does not by itself give her an Islamic right to divorce. See khula and a second wife.
Ask a mufti about your own case. This answer explains the general ruling. When the details of your situation matter, as they do here, ask a qualified mufti and give them the full facts. Where to ask a scholar.
The evidence
Quran, Surah Al-Maaida 5:1
بِسْمِ ٱللَّهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓا۟ أَوْفُوا۟ بِٱلْعُقُودِ ۚ أُحِلَّتْ لَكُم بَهِيمَةُ ٱلْأَنْعَٰمِ إِلَّا مَا يُتْلَىٰ عَلَيْكُمْ غَيْرَ مُحِلِّى ٱلصَّيْدِ وَأَنتُمْ حُرُمٌ ۗ إِنَّ ٱللَّهَ يَحْكُمُ مَا يُرِيدُ ﴿١﴾
O you who have believed, fulfill [all] contracts. Lawful for you are the animals of grazing livestock except for that which is recited to you [in this Qur'an] - hunting not being permitted while you are in the state of ihram. Indeed, Allah ordains what He intends.
Believers keep the terms they agree to.
Quran, Surah Al-Israa 17:34
وَلَا تَقْرَبُوا۟ مَالَ ٱلْيَتِيمِ إِلَّا بِٱلَّتِى هِىَ أَحْسَنُ حَتَّىٰ يَبْلُغَ أَشُدَّهُۥ ۚ وَأَوْفُوا۟ بِٱلْعَهْدِ ۖ إِنَّ ٱلْعَهْدَ كَانَ مَسْـُٔولًۭا ﴿٣٤﴾
And do not approach the property of an orphan, except in the way that is best, until he reaches maturity. And fulfill [every] commitment. Indeed, the commitment is ever [that about which one will be] questioned.
Promises will be asked about.
Sahih al-Bukhari 2721
Sahih... أحق الشروط أن توفوا به ما استحللتم به الفروج ...
"The conditions most deserving to be fulfilled are those by which you made intimacy lawful."
Marriage conditions carry special weight.
Jami' at-Tirmidhi 1352
Grading to be checked... المسلمون على شروطهم إلا شرطا حرم حلالا أو أحل حراما ...
"Muslims are bound by their conditions, except a condition that forbids what is lawful or permits what is unlawful."
The basis on which the Hanafis void conditions that forbid a lawful second marriage.
Where the ruling is recorded
- al-Hidaya, Kitab al-Nikah, Bab al-Mahr, on conditions attached to the nikah. A condition that he will not marry again does not bind; the nikah is valid.
- al-Durr al-Mukhtar, Kitab al-Talaq, Bab Tafwid al-Talaq. Delegating divorce to the wife, including tied to a condition.
- al-Mughni (Ibn Qudama), Kitab al-Nikah, on conditions in marriage. The Hanbali view that conditions benefiting the wife are binding.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.