A man has gotten rich fast, retired and retreated to a bunker on a remote (but inhabited) island. His ex-girlfriend shows up to reconcile, but he refuses. She won't leave, as she has no money for the trip back. He resorts to making her his slave secretary, putting her on a chain in his office. When an old friend visits and sees the setup, he asks the man to lock up his golddigger wife, to which he agrees. He starts to offer this as a service, locking up wives and humiliating them in video session as their husbands wish. Time goes by, the world changes, people can't afford long distance travel any longer, the husbands no longer care. A tsunami hits the island hard. The man opens the bunker to the survivors and shares the women.
Can't remember title, author, any names, the site it was published on. Read it years ago.