The duty to pay child support lies with the parents of the children (adoptive or natural). It is his order and he is the one who is responsible. That being said, you could have assets that you own jointly seized if you are not careful with how things are separated. For instance, taxes and checking accounts are seized regularly, if the non-custodial parent is on the account even if his new spouse is a joint owner. You can file an innocent spouse claim in some instances.
To properly understand the answer to your question, you must distinguish between "direct" legal responsibility, on the one hand, and "indirect" legal responsibility, on the other.
With respect to "direct" legal responsibility, the law in New York is that you are NOT legally responsible to support, or pay child support for, a step-child. The exception to this rule, however, is found in Section 101 of the New York Social Services Law, which makes a step-parent legally responsible for the support of a step-child under the age of 21 if that step-child either: a) is a recipient of public assistance; or b) is liable to become a recipient of public assistance in the absence of support by the step-parent.
So, as long as your your new husband's child or children do not become the recipient(s) of public assistance, or in need of such assistance, you will have no direct legal responsibility to support them.
With respect to "indirect" legal responsibility, New York law permits a court to "impute income" to the "non-custodial parent" of a child for purposes of calculating the amount of child support he or she must pay to that child's "custodial parent." This can be done in a variety of ways, but one of them involves the court taking into consideration "...money, goods or services provided [to the the non-custodial parent] by relatives and friends." For example, if you were to contribute to the payment of your husband's living expenses by giving him money or paying his bills, that contribution could be considered by the court in fixing your husband's monetary child support obligation. Also, if you were to enhance your husband's life style by paying for vacations or travel, entertainment, or expensive consumer goods, the court could consider your husband's enhanced standard of living in fixing the amount of his child support obligation.
When a family member's money, goods or services are considered in fixing the child support of a non-custodial parent, that family member does NOT become legally obligated to directly support the child, or to pay support to the child's custodial parent. To the extent, however, that the family member's economic contributions to the non-custodial parent serve to increase the non-custodial parent's monetary child support obligation, it can be argued that the family member has become "indirectly" responsible for the child's support.
If you are concerned about protecting your income and assets from the custodial parent of your husband's child(ren), you should consult with a qualified divorce or family law attorney to learn more about this issue.
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