The sugar mother - Elizabeth Jolley

An aging but handsome university professor, Edwin Page, is married to Cecilia, a much younger woman who is an obstetrician and gynaecologist.
(He was attracted to her in the first place by all the mysterious things she knew about the human body.)
When the childless Cecilia goes away for a year's study leave, Edwin finds himself more and more in the company of Leila and her mother who live next door.
Leila's mother is a very good cook, and Leila, it turns out, is perfectly willing to be a surrogate mother...
THE SUGAR MOTHER explores the way the many little impacts of distance, separation and change can gather force and move people in unexpected directions. It is a witty, disturbing story of self-deception and of hopes, perhaps secret hopes.