If my husband wants to adopt my son his father is not and never has been in the picture, do we still need his permission?

If your son's father has never been in the picture, I would think that he would not appose the step-parent adoption.  If the father surrenders his parental rights, upon completion of the adoption, he will no longer be obligated to pay ongoing child support payments (unless there is a court order for payment of child support arrears.  If your son's father does not want to consent to the adoption, a hearing will be held in court.  The judge may terminate the father's parental rights, depending on the evidence.  This is not the type of case that you should attempt to handle without the assistance of an attorney.