Check the laws in your state. I made darn sure my money can never be used in CS determination, but I know that your income may in fact be considered in some states (Complete BS). Much of what is shared on the tax return is all but public knowledge anyway, but trust me, I feel your sense of invasion of privacy. I wish you the best of luck!

In my state NY the step parent income is not considered. If you want to find out her info that's called forensics and you need a special attorney for that. It is extremely expensive but if you believe your DH ex is scamming you, maybe you should look into it. My cousin hired one when she got divorced because her ex was claiming poverty, meanwhile he owned a business, in the end, he lost and she won a shit load of child support for her kids.