My (house)wife is concerned that since I am the earner, I am the one who gets all the reward for giving money in charity, while she does not. Is this true?

In principle, we should understand that Allah Ta'ala's mercy knows no limits. Allah Ta'ala rewards a person on the basis of the most insignificant and minutest of actions. This is solely based on one's intentions. A person who merely intends at heart to do good is rewarded fully on the basis of his intention even though he was unable to do the action.

Similarly, here in your case, you have enough wealth to spend in charity so you will be rewarded if you spend. If your wife does not have wealth to spend in charity but she makes this intention at heart that if she had wealth, she would have spent it in charity, then she is also being rewarded fully by Allah Ta'ala on the basis of her pure intentions.

Nevertheless, in all cases the wife earns tremendous amount of reward even though she does not physically prepares for her husband, the dishes that she washes and all the other chores is in reality charity and will earn lots of reward for her.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai