Riviera Maya, Jamaica, or somewhere else? First trip abroad, want luxery, beaches, watersports and ecotourism?

Gia asked:

Would love to avoid children (sorry!) and not interested in a big party. Really just looking for a tropical paradise to escape, swim in beautiful calm water against a lush green background, possibly kayak and enjoy an adult beverage or two without completely excluding my non drinking boyfriend. Please advise and thanks so much in advance. Desperately seeking guidance!!