Reward through Husband's Earnings
The Prophet (sal Allahu alaihi wa sallam) said: "When a woman spends (in the Path of Allah) from her husband's wealth, not wasting it (but spends reasonably and within permissible limits) she will have her reward for what she gave and her husband will have his for what he earned. The same applies to the storekeeper. The reward of any of these persons does not diminish the rewards of the others." [Sahih Bukhari]
In the life of this world, the title or ownership of wealth is outwardly assigned to human beings, through apparent means such as earnings or inheritance, due to the necessity of organising the affairs of an orderly society. However, all human beings are on an equal footing in terms of real ownership of possessions, in view of the fact that it is not man but Allah (subhana wa ta’ala) Who is the Absolute Owner. The husband, the wife, and even an employee who arranges for the charity payment to be made, are all rewarded due to their respective roles in facilitating the giving of charity and not on account of their temporary ownership of what was donated.
This hadith of Rasul Allah (sal Allahu alaihi wa sallam) should be a source of reassurance to ladies that their giving in charity will earn them reward, regardless of whether they personally earned the money or not.