Sahih Muslim Book 5, Hadith Number 2238.
Chapter : Concerning the collection of Sadaqa and doing of good deeds.
Hammam b. Munabbih said: These are some of the a Hadith of Muhammad. the Messenger of Allah (may peace be upon him), transmitted to us on the authority of Abu Huraira. So he narrated one Hadith out of them (as this): The Messenger of Allah (may peace be upon him) said: No woman should observe fast when her spouse is present (in the house) but with his permission. And she should not admit any (mahram) in his house, while he (her husband) is present, but with his permission. And whatever she spends from his earnings without his sanction, for him is half the reward.