N.D. Cent. Code § 14-09-09
A stepparent is not bound to maintain the spouse's dependent children, as defined in section 50-09-01, unless the child is received into the stepparent's family. If the stepparent receives them into the family, the stepparent is liable, to the extent of the stepparent's ability, to support them during the marriage and so long thereafter as they remain in the stepparent's family. Such liability may be enforced against the stepparent by any person furnishing necessaries to such children. If an order issued under section 14-09-08.10 requires an obligee to provide health insurance coverage, any coverage that is available to the stepparent for the obligee's dependent children is considered to be available to the obligee and is enforceable against the stepparent by a child support agency. If the children are received into the stepparent's family and supported by the stepparent, it is presumed that the stepparent does so as a parent, in which case the children are not liable to the stepparent for their support, nor the stepparent to them for their services. The legal obligation of a natural or adoptive parent to support that person's children is not affected by the liability imposed upon their stepparent by this section.
N.D.C.C. § 14-09-09