Excerpt from The Children Act by Ian McEwan, plus links to reviews, author biography & more

All this sorrow had common themes, there was a human sameness to it, but it continued to fascinate her. She believed she brought reasonableness to hopeless situations. On the whole, she believed in the provisions of family law. In her optimistic moments she took it as a significant marker in civilization's progress to fix in the statutes the child's needs above its parents'. Her days were full, and in the evenings recently, various dinners, something at Middle Temple for a retiring colleague, a concert at Kings Place (Schubert, Scriabin), and taxis, Tube trains, dry-cleaning to collect, a letter to draft about a special school for the cleaning lady's autistic son, and finally sleep. Where was the sex? At that moment, she couldn't recall.

"I don't keep a record."

He spread his hands, resting his case.

She had watched as he crossed the room and poured himself a measure of Scotch, the Talisker she was drinking now. Lately, he was looking taller, easier in his movements. While his back was turned to her she had a cold premonition of rejection, of the humiliation of being left for a young woman, of being left behind, useless and alone. She wondered if she should simply go along with anything he wanted, then rejected the thought.

He had come back toward her with his glass. He wasn't offering her a Sancerre the way he usually did around this time.

"What do you want, Jack?"

"I'm going to have this affair."

"You want a divorce."

"No. I want everything the same. No deception."

"I don't understand."

"Yes you do. Didn't you once tell me that couples in long marriages aspire to the condition of siblings? We've arrived, Fiona. I've become your brother. It's cozy and sweet and I love you, but before I drop dead, I want one big passionate affair."

Mistaking her amazed gasp for laughter, for mockery perhaps, he said roughly, "Ecstasy, almost blacking out with the thrill of it. Remember that? I want one last go, even if you don't. Or perhaps you do."

She stared at him in disbelief.

"There it is, then."

This was when she had found her voice and told him what kind of idiot he was. She had a powerful grip on what was conventionally correct. That he had, as far as she knew, always been faithful made his proposition all the more outrageous. Or if he'd deceived her in the past he'd done it brilliantly. She already knew the name of the woman. Melanie. Not so remote from the name of a fatal form of skin cancer. She knew she could be obliterated by his affair with this twenty-eight-year-old statistician.

"If you do this it'll be the end for us. It's as simple as that."

"Is this a threat?"

"My solemn promise."

By then she had regained her temper. And it did seem simple. The moment to propose an open marriage was before the wedding, not thirty-five years later. To risk all they had so that he might relive a passing sensual thrill! When she tried to imagine wanting something like it for herself—her "last fling" would be her first—she could think only of disruption, assignations, disappointment, ill-timed phone calls. The sticky business of learning to be with someone new in bed, newly devised endearments, all the fakery. Finally, the necessary disentangling, the effort required to be open and sincere. And nothing quite the same when she came away. No, she preferred an imperfect existence, the one she had now.

But on the chaise longue it rose before her, the true extent of the insult, how he was prepared to pay for his pleasures with her misery. Ruthless. She had seen him single-minded at the expense of others, most often in a good cause. This was new. What had changed? He had stood erect, feet well apart as he poured his single malt, the fingers of his free hand moving to a tune in his head, some shared song perhaps, not shared with her. Hurting her and not caring—that was new. He had always been kind, loyal and kind, and kindness, the Family Division daily proved, was the essential human ingredient. She had the power to remove a child from an unkind parent and she sometimes did. But remove herself from an unkind husband? When she was weak and desolate? Where was her protective judge?

Excerpted from The Children Act by Ian McEwan. Copyright © 2014 by Ian McEwan. Excerpted by permission of Nan A. Talese, a division of Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.