You will fall in love with Aruba. My husband and I went on our honeymoon and absolutely loved it. We're going back for the third time with our two kids and my husband's parents. We're headed down on the 18th of August . We bought a timeshare because we loved it so much. We can't wait.
There is so much to do . You and your fiancee should check out the Kukoo Kunuku party bus. You will have a blast. My husband and I did it on our honeymoon and had so much fun. They take you to the California Lighthouse for a champagne toast , and then to a nice dinner and then afterwards take you to several local bars to hang out and have a few drinks. Its alot of fun and I highly recommend it. There's also the snorkeling cruises and Jeep tours through DePalm Tours. The jeep tour is a good way to explore the island. They pretty much take you all over to all the sights. You might want to consider renting a jeep on your own and explore the island on your own too. Its a small island so you shouldn't have any problems getting around although their street signs aren't the greatest. Definitely keep your eyes out for signs and which way to go.
We were told that the Balashi Beer ( Aruba's own beer) Brewery tour is something to check out so we might do that. Its neat from what we heard and of course you get free samples.
You will have a great trip whatever you decide to do. Enjoy it!