The Ten O'Clock Horses — Laurie Graham

It is 1962. The first avocado pears are appearing at the greengrocer's, people are thinking about carpeting their lavatories and boxing in their banisters, and Ronnie Glover, housepainter, husband and father, is feeling the first vague stirring of discontent with his life.
Then, out of the blue, the fabulous, sophisticated (and married) Jacqueline bursts into his life and teaches him to tango. She seems to offer everything he ever dreamt of. But is it all too good to be true?