Hi there, Denise!
Most of the childcare facilities at the Deluxe Resorts open in the late afternoon (around 4:00 PM) and go from there. If you are staying at one of these Resorts, you are welcome to put your children in one of the clubs for a nominal fee if you can get a later appointment.
Walt Disney World recommends,
on its Saratoga Springs Resort and Spa page, a service called Kids' Nite Out:
"Together with independent childcare provider Kids Nite Out, Disney's Saratoga Springs Resort & Spa offers the convenience of one-to-one in-room babysitting for children 6 months to 12 years old. You can even reserve a childcare specialist to accompany you and your family during your visit to the Parks, providing a helping hand where needed.
To make a reservation for in-room babysitting ... call (407) WDW-DINE or (407) 939-3463 up to 180 days in advance. Guests under age 18 must have parent or guardian permission to call."
You do not have to be staying at Saratoga to take advantage of this service, but I would wholeheartedly recommend the facilities at Saratoga as the perfect option for your couples' massage.
And setting your children up in your Resort room with a provider specifically endorsed by Walt Disney World ought to provide you with the peace of mind to really relax and enjoy the experience.
Happy anniversary!
See you later, celebrator,
-Deborah B.