We were just in PDC last week. Before we left, there was lots of rain & thundershowers showing up in the forecast. But while we were there, it rained only once, and I would barely even call that rain. We didn't even bother to get up off our loungers.
I've been to the area 5 times and now and, as others have mentioned, these forecasts don't seem to be all that accurate. Or the forecast images are misleading. If you drill down into the forecast details, you might find that it's only a 30 or 40% chance of less than 5mm of rain (0.2 inches). And it can also be isolated - so it might rain a little further away in the jungle, but not at the beach.
If it does rain, your WC will make sure everything goes smoothly. They are experts at this and know how to handle it. But my WC told me that he only had to move 4 weddings inside last year! Fingers crossed for you!
Congrats! Hope you had a fabulous time and that you'll do a review of your stay and post pics! The ladies here love to see the photos!!