Any mail that came to me addressed as Mr and Mrs Richard Ricardo would be sent straight back unopened. I cannot believe that in today's age of equality (supposedly) any professional body would do a woman the discourtesy of making her no more than an appendage to her husband, to the extent that she no longer has her own first name.
My "other" vote would be "Lucy and Richard Ricardo." Why the hell should he be first? Do you know for sure that he is the one taking care of all matters financial, legal and administrative in the family? In our house, that would not be the case. Most of the accounts in this family are held in my name and as such, I expect all mail concerning those accounts to address me first.
I'd do my research before addressing anything to anyone.
Clare