For two days, I’ve slept in my own wing of an echoing estate on a billionaire’s private island and been rendered helpless by a butler attending to my every need. I’ve gobbled three-course lunches, guzzled rum cocktails and champagne, worked out solo in a fully equipped gym, bathed in a bathtub the size of a boat, and had a gleaming yacht at my disposal. I’ve taken sunset dips in the Caribbean-my footsteps quite literally the only ones in the sand. Suddenly, it’s hard to imagine not vacationing like this all the time. Dare I say, I’m starting to feel entitled.

I’m in the Caribbean on Calivigny Island, just off the south coast of Grenada, where for $165,000 a night, you and up to 59 of your closest friends can inhabit the personal vacation paradise of a French businessman and his wife, including the 19,000-square-foot main house, two pools, five outdoor hot tubs, four boats, and a 30-person permanent staff.

Though the price may seem a little astonishing, there are quite a few ultra-affluent travelers who can afford it-and their ranks are growing. Last year, more than 2,000 people on earth were worth $1 billion or more, 185 more than in 2011, according […]