The Younger Wife by Sally Hepworth 

A heart surgeon at the top of his field, Stephen Aston is getting married again. But first he must divorce his current wife, even though she can no longer speak for herself.

Tully and Rachel Aston look upon their father’s fiancée, Heather, as nothing but an interloper. Heather is younger than both of them. Clearly, she’s after their father’s money… Read more.