Originally Posted by LadyB
Her other children shouldn't matter as she should be getting support from their father(s), as the support is only for the child/ren from a single relationship and most states require you follow their formula. He needs to get it formalized in court if at all possible (he would need an attorney), too bad if she is reluctant, she has to disclose her income to work this out.
Perhaps his Child Support Enforcement department has some information and guidance for him, they would probably find it a nice change of pace to hear from someone who actually wants to pay. I don't know if they will acknowledge private agreements, he needs to call and discuss it with them at least.