Hello @Sallyann-And-David0,
Sorry, I misread your first post and thought that you wanted to change TO using your husband's email address. My fault.
I've never used the Facebook login so don't know what bearing it has when you want to change email addresses.
Do you have any other Airbnb account where the [email address hidden] email address has been entered?
If not then the best thing to do is to contact Airbnb customer support.
Type "contact airbnb" in the "Search the community" box on the help forum web pages where you posted this question.
That will show up a list of suggestions one of which is "Contact Airbnb: A Community Help Guide". Click on that to see phone numbers and information on other contact methods.
Steve.