This is very tough!! This is YOUR WEDDING and you have to do what makes you happy! If being on the beat in St. Lucia is the wedding of your dreams - then you need to not look back and just know that those that can make it there will be there. If having everyone there is the most important thing to you (and you know realistically they cant handle the trip) then you have to weigh whats most important to you. Personally I was going to have my wedding at home, however, my guest list was getting to be out of control and felt a lot of pressure and not to mention the cost that I was starting to rack up!! So 2 weeks ago we decided to cancel the wedding at home and take off. We know that not everyone will be able to make it, but I know that the most important one's can make it. They find a way one way or another.
That was long winded but you have to be selfish - I made a lot of people mad, but at the end of the day its about you and him. What will make you happy - you only get to be selfish once! Good luck!!!