At Sea by Laurie Graham
When Lady Enid - a woman in need of a project and a husband - throws in her lot with dashing Bernard Finch, she thinks she's found her perfect life's companion. Handsome and clever, Bernard has come a long way from his small-town American roots. Now he is a man transformed, more English than the English, a celebrated lecturer on Aegean cruises. Which is where his past comes back to bite him, in the shape of his old college chum, Frankie Gleeson. Frankie has made his fortune in corn snacks and to celebrate his success he brings his wife, Nola, to cruise the Greek islands. Frankie is a simple man but he has the gift of total recall, of every detail of Bernard's early years. Yet while Bernard shuns his cruise companions, Enid finds herself strangely drawn to them. It's amazing how much can happen between Istanbul and Venice.