If you add the spouse info the criteria sets, it will allow you to match the incoming data to the Head of Household record in RE.
You can also opt to ignore spouse matches if a main constituent matches (should your spouse be a constituent relationship rather than a non-constituent relationship).
The 'Spouse' setting will allow Importacular to search if a record has a spouse and seeks to match on First Name, Middle Name and Last Name/Surname if there is one. If a Maiden Name is present on the record, it can also look to match there.
Note: Selecting 'Spouse' does not seek to match on a Spouse's other details like address or email address.
If you're working with an Head of Household record with a non-constituent spouse and you want to import to the constituent, the Spouse option can enable you to do so (but absolutely make sure that you uncheck the option to update fields for existing records as needed so that you don't have Mary and Mary Jones instead of John and Mary Jones). You can do this on individual fields using the Field Settings.