Anyone know of some great, low-key, secluded vacation spots in Mexico or the Caribbean?

My husband and I really need to unwind! We aren’t exactly Cancun ‘type’ party goers, and are looking for a great spot in Mexico or the Caribbean to drink beer, lay in the sun, maybe snorkel some and RELAX! We have looked at the Sandals Resort packages, but they seem a liiittle pricey. Any suggestions? My sanity thanks you! 🙂