If I understand you correctly, he is already depositing $5000 tax free in your account each month. Please clarify if that is true or not. That's equal to about a $85K taxable income, plus the $20K you earn. Using an online calculator, his net pay on $200K after taxes, is $10,200 month, and that's if he's putting zero into retirement. In other words, he's already giving nearly half his income, which is more than likely significantly more than a court will award. And, whatever the award may look like in the future, it will be tax deductable to him, and you will have to pay taxes on it.