It's in His Kiss: The 2nd Epilogue (Bridgertons 7.5)

He leaned down and took one rosy-tipped breast into his mouth before she could object.

“Oh, Gareth!” And her knees went weak. Just enough for him to scoop her up and take her to the sofa. The one with the extra-deep cushions.

“More?”

“God, yes,” she groaned.

He slid his hand under her skirt until he could tickle her senseless. “Such token resistance,” he murmured. “Admit it. You always want me.”

“Twenty years of marriage isn’t admission enough?”

“Twenty-two years, and I want to hear it from your lips.”

She moaned when he slipped a finger inside of her. “Almost always,” she conceded. “I almost always want you.”

He sighed for dramatic effect, even as he smiled into her neck. “I shall have to work harder, then.”

He looked up at her. She was gazing down at him with an arch expression, clearly over her fleeting attempt at uprightness and respectability.

“Much harder,” she agreed. “And a bit faster, too, while you’re at it.”

He laughed out loud at that.

“Gareth!” Hyacinth might be a wanton in private, but she was always aware of the servants.

“Don’t worry,” he said with a smile. “I’ll be quiet. I’ll be very, very quiet.” With one easy movement, he bunched her skirts well above her waist and slid down until his head was between her legs. “It’s you, my darling, who will have to control your volume.”

“Oh. Oh. Oh…”

“More?”

“Definitely more.”

He licked her then. She tasted like heaven. And when she squirmed, it was always a treat.

“Oh my heavens. Oh my…Oh my…”

He smiled against her, then swirled a circle on her until she let out a quiet little shriek. He loved doing this to her, loved bringing her, his capable and articulate wife, to senseless abandon.

Twenty-two years. Who would have thought that after twenty-two years he’d still want this one woman, this one woman only, and this one woman so intensely?

“Oh, Gareth,” she was panting. “Oh, Gareth…More, Gareth…”

He redoubled his efforts. She was close. He knew her so well, knew the curve and shape of her body, the way she moved when she was aroused, the way she breathed when she wanted him. She was close.

And then she was gone, arching and gasping until her body went limp.

He chuckled to himself as she batted him away. She always did that when she was done, saying she couldn’t bear one more touch, that she’d surely die if she wasn’t given the chance to float down to normalcy.

He moved, curling against her body until he could see her face. “That was nice,” she said.

He lifted a brow. “Nice?”

“Very nice.”

“Nice enough to reciprocate?”

Her lips curved. “Oh, I don’t know if it was that nice.”