I may be getting a divorce. My husband and I have one child together and I brought my son into the relationship. We have been married since 2010. If the divorce goes through is my husband responsible to pay supports for both children or just our child together?

More than likely just one, unless he adopted your child from a previous relationship.

Unless he adopted the child, the real bio father is the one, who should be paying support now, and later, a step child is not the responsibility of a step father unless adopted