Excerpt from A Certain Age by Beatriz Williams, plus links to reviews, author biography & more

She doesn't know, poor thing, that in less than a year, she will discover that her husband keeps a mistress, and that this mistress has also borne him a child—a small and perfect daughter—only two months after the birth of the Marshalls' own firstborn son. By then, of course, the portrait's subject will be several months into her second pregnancy, and she will face an important decision, the most vital choice of her life, and one on which all her future happiness depends.

Did she make the right one?

Well, I'm here, aren't I? I stand right here in the shabby attic of an old carriage house, as rich as ever, mother of three cherished sons, wife of a generous and well-respected husband, passionately in love with a young and brilliant man—a man to whom I have no earthly right, a man who returns my passion with bone-snapping physical ardor—who at this very moment has flattened himself into the dust beneath the bed for my sake.

What more could a woman ask for, at my age?

I'm halfway through the cigarette before I address the question warping the eyebrows of the brother who stands before me. I wave away a curl of smoke, which has been illuminated into a kind of celestial spirit by the sunshine that now refracts through the window's ancient glass. The luminous new morning of the second of January. Remember that.

"Do you happen to know the young lady's name?" I ask.

My brother says eagerly, "Sophie. Sophie Fortescue. She's a good girl, Theresa. Quiet as a mouse. The sweetest girl in the world. Wouldn't say boo to a goose."

I hand him the cigarette—he looks as if he needs a smoke more than I do—and he sucks it in like oxygen. I look past his elbow at the bed in the corner, and the dozen or so mildewed horse blankets that the Boy gathered up to cover me last night. I objected to the smell, and he said a little mustiness was better than freezing to death, and anyway I'd get used to it. Human beings can get used to anything, he told me. It's how we survive.

And he was right. All I remember of last night, other than the terror of my dream, is the smell of the Boy's warm skin.

I return my gaze to the pasty and anxious ruins of my brother's face. "In that case, I can't begin to imagine what she sees in you, Ox, though I frankly can imagine why your courage failed you, in the face of all that virtue."

He begins to object, and I hold up my hand.

"Nonetheless, and to your great and undeserved fortune," I continue, "I happen to know just the boy to get the job done."

Excerpted from A Certain Age by Beatriz Williams. Copyright © 2016 by Beatriz Williams. Excerpted by permission of William Morrow. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.