Last April was our 10-year anniversary. DH gave me three choices: cruise, Yellowstone, or Nashville. I chose Nashville, but the cabin wasn't available. So I chose Yellowstone and we booked it, but they had a late snowstorm and the park was closed. So on a whim we took a cruise. AND LOVED EVERY SECOND OF IT. On my profile there's an album of pics from last year.
While on board we booked for 2017, to bring the kids. Everything we did we only wished they were with us. We also put out an invite to other married friends, and two couple came to. It cost us around $1700 for the four of us. Considering the quality of food and the 12+ hours a day of childcare available, I still think it's a heck of a value. There's also music shows/productions, comedians, and games every day/night. They play movies on board and have tournaments for bean bag toss and trivia. In ports you can leave the ship and walk around to shops or public beaches for free. So you can definitely keep costs down.