Roommates Wanted, by Lisa Jewell

Fun, charming London chick-lit, from Sophie Kinsella's Very Short List of 5 recommended titles. Toby Dobbs inherits a large london house, and fills it with lodgers. 15 years later, he needs to move on in his life, and with a neighbor, starts trying to sort out how to get them all to move on to happier, fuller lives.