Heat Wave by Penelope Lively

Pauline is spending the summer at World’s End, a cottage somewhere in the middle of England. This year the adjoining cottage is occupied by her daughter Teresa and baby grandson Luke; and, of course, Maurice, the man Teresa married.

As the hot months unfold, Maurice grows ever more involved in the book he is writing about the myth of the British countryside. Pauline, editing a novel about romantic love, is drawn again and again to the years when, imprisoned and crippled by jealousy, she stayed with Teresa’s father despite his constant infidelities. With anguish and mounting anger, Pauline becomes aware that Maurice will similarly betray Teresa. Heat and tension build to a startling climax.