How can a married man be fair between two wives regarding spending, given their different situations (one employed and the other unemployed), and should the spending be according to each wife's needs?

A husband must provide for his two wives equitably, with what suffices their needs, and he is not obligated to be just between them in what exceeds that. The salary of an employed wife is her sole property, and the husband is not permitted to dispose of it, nor does this diminish her obligatory maintenance.