I know you like an on-site pool, but I still think you should give Bar B Barn a long look. The rooms and beds are nice, the AC is great, the food is amazing (at Angelas, the entrees are big enough to split into two meals), and best of all you ask them do something one time, and it gets DONE .... That's a nice thing in Negril.
Also, the three times I've stayed at BB Barn, there was an unofficial agreement with Coral Seas across the street that you could use their pool.