I'm the family cruise editor at CruiseMates.com. What ports are on your itinerary: Cozumel, Grand Cayman, Jamaica? It'd be helpful to know.
Definitely stay with your teens in Jamaica, even on a shore excursion. Jamaica is beautiful but your kids will get hassled (as all tourists do) there. Grand Cayman seems to be a very safe environment even if your teens want to go shopping independently in town. (Note that you will have to take tenders from your ship to port.Make sure they know when the last tender leaves from the port to your ship.) If you do opt for the Mayan ruins with your husband, be aware that your youngsters will be without you for a very long day.(The shore excursion I went on to the ruins was about 7 hours -- hot and dusty but definitely worth it!) If there are any other ports on the itinerary I missed, let me know.