I'm not a Georgia attorney, but I'd like to know where your husband's ex-wife went to law school.  She's way off base.

Unless your state's law is very different from most (possible, but unlikely), your income has nothing to do with your husband's child support.  Nothing at all, period.  Her income certainly does get considered, although it doesn't make much of a difference in practice.

Your husband might be able to get a reduction in child support, based on having to support the daughter you share.  However, to do this, it will probably be necessary to disclose your income (since part of the process is figuring out what his child support would be if you separated), which wouldn't be required otherwise.

Actually, in Georgia her income plays a large part.  The child support laws in Georgia were changed in 2007.  We now have a child support spreadsheet which takes the income from both parents, the expenses for the child, and calculates a percentage for each parent.  Then the non-custodial parent pays whatever amount that percentage of his/her income is awarded, to the custodial parent.  There are a number of deviations that can be requested from there, but it is the judge's discretion as to how much of those deviations are actually counted.  Most judges will follow the child support worksheet to the penny. If your husband has had a substantial change in circumstances, it is quite possible that he can get his child support reduced. 

Your income is not figured in.