I suspect that you are more concerned about your new engagement ring than any other jewellery you might be bringing. I would not worry about it with this sole exception. Make sure it fits well. I have noticed in the past that my hands swell from the heat and humidity while in the DR, but this does not mean that you can't lose it while swimming, with all of that sunscreen on your hands. I have seen it happen. Believe it or not, the lady lost a 1 ct. diamond engagement ring, and her husband found it again while snorkelling. really.
Enjoy this special time of our life and wear your ring with pride. JUST MAKE SURE IT FITS,
and have a great time. I know you will.
Rose