Congratulations on your upcoming anniversary! You did say it's your anniversary in your original message. May you always be on your honeymoon!
Bermuda is about the same latitude as South Carolina, and the weather is often comparable. It should be great weather for walking, hiking, golf, and sightseeing. It may well be too cool to go into the water, however.
There is a lot to see and do in Bermuda that doesn't involve being in the water. Hamilton is a nice city to walk around, with good shopping, bookstores, and the like. King's Wharf
has a maritime museum, and has been built up in the last several years with arts and crafts shops. There's also a wonderful Bermuda Aquarium, Museum and Zoo
which is reachable via Bermuda's wonderful public bus system from Hamilton or King's Wharf.
Coming from the northeast, I think sitting on deck in 65-75 degrees sounds great. If you're used to, or interested in, warmer weather where you are, it may not seem as attractive.
Explorer is a wonderful ship. If you're able to drive to embarkation in either Cape Liberty or Baltimore, all the better!