Step-parents may be obligated to pay child support to step-children they had during the relationship, depending on the extent of their involvement with the child(ren) during the relationship, and the extent of child support being paid by the biological parent.
The following two cases outline the factors that will be assessed by the court in determining this:
For a quick review, begin reading at paragraph 21 of Omeltchenko and paragraph 6 of Gilchrist.
Write something about yourself. No need to be fancy, just an overview.