St. Lucia or Italy for our honeymoon?

My fiance and I are trying to plan our honeymoon (Scheduled for late november) and we can't decide if we want to go to St. Lucia in the virgin islands, or travel around italy. We're both seasoned travelers but have not been to either place. We know the trips are two completely different experiences- one involves exploring the rainforest and sitting on the beach, while the other involves sightseeing and experiencing a different culture. We like both ideas equally, although we worry the sightseeing in italy will be stressful. We once traveled around japan and felt like we needed a vacation after our vacation- there was just so much to do/see! Anyway, if you have been to either place, let me know what you think! Thanks!