Marrying the Mistress - Tapa dura

Simon Stockdale spells it out for his son Jack: 'Your grandfather is proposing to leave your grandmother to whom he has been married for forty years and marry a woman with whom he has been having an affair for seven years.'
'Grando?' marvels Jack. 'Grando wants out and to start again?' What can this mean to a boy in the throes of his first love affair? Or to Simon's wife Carrie who always thought her wronged mother-in-law was one of the most self-pitying women she'd ever met anyway? Filial debts are about to be called in and Carrie doesn't want her husband Simon to pay them. Yet Simon feels a bond of obligation towards his mother which makes him vulnerable - and which no one else can fathom.
And what of the mistress - a barrister who has fallen in love with a judge twice her age? What if she isn't just 'His Honour's totty', as one court official labels her. What if, as Simon's gay brother Alan decides, 'She's the real thing. She's a proper person.'