The Woman in the Sable Coat by Elizabeth Brooks

From the acclaimed author of The Orphan of Salt Winds, The Whispering House, and The House in the Orchard comes a passionate and fateful story of love, betrayal, and the rewards-and costs-of following your heart.
At the height of the Second World War in England, twenty-two year old Nina Woodrow joins the British Royal Air Force and rebels against her careful upbringing by embarking on an illicit affair with an officer. She risks losing everything for Guy Nicholson: her comfortable home, her childhood friends, and, especially, the love of her father, an enigmatic widower. Meanwhile, in the sleepy village where Nina grew up, where the upheavals of war seem far away and divorce remains taboo, Kate Nicholson struggles to cope with her new role as the wronged wife. She finds an unlikely confidant in Nina's father, Henry, and as they grow closer Kate finds that she's embroiled in something much murkier, and more menacing, than a straightforward friendship.
Sweeping and impassioned, with pitch-perfect period detail, Elizabeth Brooks' The Woman in the Sable Coat tells the story of two families fatally entangled in one another's deepest, darkest secrets.