L&M possibly may not charge for a spouse. When I was going with my adult nephew they asked whether or not he was a spouse, so I suppose they would not have charged if he was.
Here's the info from their website:
Additional Driver
The additional driver must qualify in the same manner as the primary renter, but will not be held responsible for the payment or damage.
A fee of $5.00 per day will be charged for each additional driver.
This charge can be waived if the additional driver is a spouse or life partner.