A Long Walk in Wintertime by Libby Purves

Alice McDonald has escaped all the obvious traps that lie in wait for women. She loves her job but enjoys her clever, spirited children too; her husband (Dan the New Man) does his share at home, and their London house is always full of friends. At her thirty-seventh birthday party, Alice reflects that their life has been a pretty successful production so far.
But love can be treacherous, and children are never quite what they seem. Two months later, far from home and alone on a desperate quest through the bleak lanes of Norfolk, Alice wonders how it fell apart so quickly. Were things ever as good as they seemed? Had the McDonalds really been happy, or was it no more than a stage illusion?