Is it permissible to take money from the husband's wallet without his knowledge to buy household necessities, with the intention of not returning it, in order to avoid the embarrassment of asking him for money again?

You are not permitted to take anything from your husband's money without his permission as long as he is spending on you reasonably. If the money he gave you for expenses runs out, inform him and ask him for reasonable maintenance. It is not permissible for you to take without his permission under the pretext that you are embarrassed to ask him for maintenance.