Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "No woman should fast while her husband is present except with his permission, and she should not permit anyone (into his house) in his presence without his permission; and whatever she spends from his earnings without his instruction, he will receive half the reward."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7850