Since money given by a husband to wife is Nafkah that is compulsory in Syariah, it is not counted as wife’s income.
If a husband has already given sufficient Nafkah to his wife to cover all her needs, and on top of that gives a cash allowance that exceeds her basic needs, then such excess can be considered the wife’s income that is not from a source of employment.
This is because free income is a category that the Selangor State Fatwa Committe decided in 2017 will be subject to Zakat.
Reference: Matter 2, Compilation of Syariah Questions Records March - June 2023, approved by the LZS Shariah Advisory Committee Meeting