Q 2: What is the meaning of
Can this occur from both spouses or the wife only?
Nushuz is the state when one spouse violates their marital duties. Allah says:
And if a woman fears cruelty or desertion on her husband’s part, there is no sin on them both if they make terms of peace between themselves; and making peace is better.
A woman may give up any of her rights so that her husband would not divorce her, as
Sawdah (may Allah be pleased with her) did with the Prophet (peace be upon him).
`Aishah (may Allah be pleased with her) (Part No. 19; Page No. 379) commented on Allah's Saying:
And if a woman fears cruelty or desertion on her husband’s part
this refers to a woman who is married to a man who does not want to keep her any longer and wants to divorce her and marry someone else. She asks him to keep her and not to divorce her, and marry someone else too. She also frees him from supporting her financially or giving her a share of his time. This is what Allah says:
...there is no sin on them both if they make terms of peace between themselves; and making peace is better.
In another narration, she says:
The husband notices something unpleasant about his wife, such as old age or the like, and wants to divorce her, but she asks him to keep her and provide for her as he wishes. She said: "There is no blame on them if they reconcile (on such basis.)"
(Agreed upon by Al-Bukhari and Muslim)
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.