I don't want to tell you !!! I don't want to share my find ... ahahaha just kidding.
I have not been there before but the place gets great reviews. I have read about them on here, on trip advisor, and on cruise critic. The comments are all overwhelmingly positive.
They are a restaurant/bar on the beach in Mahahual - the small town right outside of the port in Costa Maya. It is on Malecon beach. You would need to take a short cab ride(5 mins or less) to get there. You email Steve in advance to reserve loungers or a table. That part is free - all that they want in return is for you to order food/drink while there. They can also arrange for some snorkeling, fishing, boating etc as well as massage for very good prices. I figured it was a better option then paying for an AI because of how short a time we are in port. The food and drink prices are super reasonable. There is also a mile long "walk" that has shopping and what not.
This is the website:
http://www.sandalsandskis.com/Tropicante.html