There have been cases where a debt that was brought into the marriage, such as arrears of support, has been excluded from a division of property. But there is generally no basis for courts to divide property unequally due to ongoing expenses paid during the Marriage. A court would look at this ongoing child support as a family obligation and would be very unlikely to divide property unequally or try to apportion responsibility for this expense. Generally the court does not go back and look at who made what payment or who was responsible for expenses incurred during the marriage. The exceptions are those expenses that can put the entire household finances in jeopardy and are taken on by one spouse without the knowledge of the other, and have no real connection to the family unit, such as gambling debts. Even then, a court would usually only look at the amount of debt existing at separation and exclude that from the division of property, nd not look at all prior money lost months or years earlier to gambling.

I wish I could point you to some useful case precedent but I am not aware of any decision that has ruled in the manner that you describe.