The Boss and a Mariane from Costa Rica visited Hidden Beach during the summer of 2009. It was the bosses idea to take advantage of Mexico's Swine Flu troubles. Even so Hidden Beach was expensive. Normally the rooms run around $500/night. But you can't beat stepping off your private patio right into the pool.
Each of the ground floor rooms have private patios with steps into the pool and a cocktail table and bench seat right in the there. The place is beautiful. There's also a hot tub, beach beds, a protected beach. etc. There's a swim up bar where most of the action is during the day. A lovely out door diningroom. An indoor buffet and and open air disco with another hot tub.
Everything is the very best, there's even 24 hr room service (except the early morning stewards are from the textiled El Dorado resort next door so be kind and don't answer the door with your nipple clips on.)
Officially, this is a nudist resort and not a "lifestyle resort." The Boss and Mariane didn't see any public sexplay but we understand they do have the occasional lifestyle take over.
For more information check out www.sexcation-review.com/Travel-NA-Mexico.html

Castaways lists two very small nudists resorts next to Tullum