There is a question on the 'Declarations' page of a loan application that specifically reads: "Are you obligated to pay alimony, child support or separate maintenance?"
In this case, since you are not oblugated to the payments you make (i.e. court ordered) then you would be able to truthfully answer 'No' to that question and be completely honest in doing so. Keep in mind that underwriters typically want to know things like that because an obligated payment is deemed to be similar to any type of monthly debt payment (car, credit card, etc). If it is an obliagtion, then they will add the debt into the ratio calculations. Since you pay it volunatrily and could stop at any time, there is no need to add it to your debt ratios.
If you have any questions about the loan process, feel free to let me know.
Bank of America Home Loans