Creating Couples as a Single 'Individual'
It would be better to create a relationship between the two - the Partner relationship type is there out of the box.

This will take account of each partner having different email addresses and different mailing preferences. Even different addresses. 

You mailing list can be created from an Advanced Search for the Partner relationship with no difficulty. 

All this allows you to segment your contacts more usefully.

This approach also negates the problem you add about searching on name.