Child support in Texas is calculated on the net resources of the person paying the support (the “obligor”), taking into account the cost of health insurance and how many children the obligor has a duty to support. For example, as in your case, if there are two children, and there is a third child now in the obligor’s household, for whom there is a duty to support, the calculation is 22.50% of the net resources for the support of the first two children. This is a reduction from the 25% that would be paid for the two children in the absence of the third child in a different household. There may be other factors that should be considered. The way to address this issue is to file a Motion to Modify to reduce the child support payment.