Disobedience (nushuz) can occur from both the man and the woman.
As for the man's disobedience, it is as Allah
سبحانه وتعالى, the Mighty and Majestic, says in His Book:
"And if a woman fears ill-treatment or aversion from her husband, there is no blame upon them if they reconcile between themselves, and reconciliation is better" (Surah An-Nisa
4:128)
This refers to a situation where a woman is with her husband, but he is displeased with her and intends to divorce her. She then says to him, "Keep me and do not divorce me, and I will relinquish what is due to me and allow you my day and night."
This arrangement becomes acceptable to him. This was narrated by Al-Mufaddal ibn Salih from Zayd Al-Shahham from Abu Abdullah
عليه السلام.
When a woman becomes disobedient (nashiz) like a man's disobedience, it leads to khulʿ (a form of divorce initiated by the wife). A woman's disobedience is when she does not obey her husband in matters of intimacy.
This is as Allah
سبحانه وتعالى, the Mighty and Majestic, says:
"And those [wives] from whom you fear arrogance [disobedience]-advise them; [then if they persist], forsake them in bed; and [finally], strike them. But if they obey you, seek no means against them. Indeed, Allah
سبحانه وتعالى is Most High, Most Great" (Surah An-Nisa
4:34)
Forsaking them in bed means turning his back to her, and striking refers to gently striking with a miswak (tooth-stick) or something similar, in a kind manner.
If they obey you, then do not seek a way against them, for Allah
سبحانه وتعالى is Most High and Most Great.