Welcome to the Search and Reunion Message Board!
Does your husband have his non-identifying information from the adoption agency that would say if birth parents were married? You might check marriages for those names in the county of birth to see if you can find a marriage record for either of the names.
California Website:
Other great websites to check out:
http://www.adoptionchat.com
http://www.adoption.com
http://www.adopting.org
http://registry.adoption.com/