From the Dollar Web site, it appears the answer would be yes, the spouse is considered an "additional driver" and the "additional driver fee" will be assessed. But it also says requirements vary by location. I guess you will find out for certain when you get there. Expect/budget for yes, and be glad if no.
D. Additional Authorized Drivers and Fees: All additional authorized drivers are required to qualify to drive the vehicle. To qualify, DOLLAR requires all additional drivers, including spouses, to satisfy our minimum age requirements, have a valid driver’s license and pay an additional driver fee. However, the following additional drivers do not need to pay an additional driver fee or separately qualify as long as they meet our minimum age requirements and have a valid drivers license:
(1) government renters on official orders,
(2) corporate account customers on corporate rate plans, and
(3) drivers/companions of physically impaired customers. The additional driver may also be subject to a driver record check and an underage drivers fee. (See below). Because the requirements vary by location, please refer to the Local Policies for specific information on additional driver fees charged at the location where you intend to rent.