If it's the spouse it's free at all but Hamptons, but if it's not the spouse they may charge. Spouses , by the way are not entitled to any of the freebies, though most hotels still give them.
From the rules
Spouse Stays Free: The additional person room charge will be waived on every qualifying HHonors stay. The additional person is not entitled, however, to any benefits associated with a package purchased at the single room rate (for example, a single room rate which includes Continental Breakfast). Not available at Hampton Inn, Hampton Inn & Suites hotels or All-inclusive hotels.