Ian McEwan "The Comfort of Strangers"

Colin and Mary are on holiday in Venice. They are growing weary of each other. They spend long, lazy days in their hotel or wandering the streets, often getting lost. One night they set out late in search of restaurant and lose their way, they meet a man named Robert who takes them to a nearby bar and, later, to his home, he leads them though the city and away from their ordinary lives...
This story stays with you long after you turn the last page.
Tanya