Financial aid is intended to be used for academic and living (individual student) expenses only. When a school factors in the cost of living (rent, food, transportation, etc), and the total tuition cost for your education, you do not consider that you may have a husband/wife/children. They usually also tell you that financial aid should not be used to pay off credit cards or other such bills and debt (including a mortgage). If you do have a significant other, they are expected to make enough of a financial contribution to make all your ends meet - so as to lessen the burden of stress that a professional school adds to our already crazy lives.
I know it's tough - but that's the way it goes (at least at the universities I have attended).