There's nothing special that prompts him to say it.
They're lounging in the living room on a rare shared day off. Everyone else has gone off to bed and Kotoko is curled beneath a blanket, hair piled in a semi-neat bun on her head with earbuds in. Naoki can faintly hear the muffled, steady beat of a pop song. She's working on the nursing plan for the next day and tapping her toes along to the music, occasionally brushing against his leg with a socked foot which is making it increasingly difficult for him to focus on his own work.
Usually, he'd push her away or move somewhere else. He's starting to do just that, halfway into pushing himself off the couch, when he glances over at her and sees her nose scrunched up cutely in concentration, her tiny, pink tongue stuck out the side of her mouth. Suddenly, he can't find it in himself to be annoyed. Instead he smiles fondly and settles back into his seat.
The face she's making reminds him of the nights they spent together in high school, with her constantly distracted by his proximity and him equally affected but covering it up by leaning into his annoyance with her. He hadn't understood then why his heart rate picked up every time he caught her staring at him or when their hands brushed as he explained a math problem to her for the fourth time. He was too arrogant then to allow himself to stare openly at her like this, sure that the feelings were temporary.
She'd come flying into his life like the meteor that destroyed her house. Tiny, loud, and devastatingly destructive. He hadn't even known his foundation was faulty until she'd knocked it all down right in front of him with a bright smile and a shrug. He'd assumed that she'd eventually exit the way she came and he'd be able to re-focus and clean up the mess. Now, over a decade later, he's still cleaning up the messes she makes. Sometimes literally.
Kotoko glances over at him and does a double take when she notices him staring. She smiles at him shyly and plucks one of her earbuds out.
"Was the music too loud?" she asks, grabbing her phone to turn it down.
Naoki shakes his head but doesn't stop looking at her.
"Do I have something on my face?" She swipes at her mouth with the back of her hand. When Naoki shakes his head again her brows furrow in confusion. "What is it, Irie-kun?"
"I love you."
Naoki expects a positive reaction but the words hang in the air for several seconds before Kotoko reacts. What passes over his wife's face is something between shock and fear. Her eyes widen and the breath she takes in sharpens at the end. He watches, intrigued and just slightly alarmed, as she reaches up slowly and takes the other earbud out.
"Are you sick? Am I sick? Did you cheat on me? What's wrong?" Kotoko suddenly starts moving faster, spitting out all her questions at once. She moves to her knees on the couch, the blanket she had wrapped around her forgotten on the floor. She places one hand on Naoki's head and the other on her own for comparison.
Naoki stares up at her for a moment before huffing out an annoyed breath and grabbing her wrist, yanking her down to his level. She lands on top of him with a huff of her own, her weight pushing him back against the couch cushions. She scrambles a bit, trying to right herself, but he only lets her get so far before pressing a flat palm between her shoulder blades to keep her in place. Her giant eyes search his face in confusion when he pushes an amused breath out his nose and reaches up to place his other hand on her cheek.
"Idiot. Am I not allowed to say it?"
"O-of course you are. I jus-" Kotoko gasps and stiffens in surprise when he cuts her off by pressing his lips against hers. She relaxes into him when he slides his hand up from between her shoulder blades to the nape of her neck, kissing her more insistently.
Naoki registers the click of a camera somewhere in the depths of his brain but instead of stopping he moves the hand on her cheek, dropping it to her thigh and pulling her lower half closer to his, drawing another gasp from her lips. He breaks the kiss to stand, sliding both hands underneath Kotoko's thighs and lifting her up with him.
"Irie-kun?" Kotoko looks at him, slightly dazed, her lips and cheeks flushed.
He moves swiftly up the stairs with her in tow, pressing chaste kisses to whatever part of her is closest when he's not watching his next step. He kisses her fully on the lips again when they make it inside their bedroom, pushing the door closed with his foot and moving toward the bed.
Kotoko giggles when he drops her on the bed, the bounce of the springs causing the space between their lips to fluctuate several times. He follows quickly after her as she slides toward the top of the bed with a mischievous glint to her eye.
Naoki pulls at the pencil she was using to keep her hair tucked away as she worked and tosses it in the general direction of their shared desk, watching as her hair slowly cascades down over her shoulders. She lets out a high pitched noise from the back of her throat when he wraps his hands around the back of each of her knees and pulls her to him, causing her to land flat on her back as he settles himself between her thighs. Her dark hair is splayed out in every direction and he's careful not to pull at it when he puts his weight onto his forearms, leaning in to kiss her again before trailing his lips down her jawline to her neck.
"Did I hear a camera click earlier?" She asks, squirming against him, fingers tangling in the fabric of his t-shirt.
Naoki hums against the junction of her throat and nips at the delicate skin. Of course she would choose that moment to suddenly be observant.
"Your mother is going to know why we came up here."
She's trying to sound firm but her voice turns breathy when his tongue darts out and licks a stripe between the first button of her top his nimble fingers have already managed to open.
"Not my problem."
His lips move further down as he makes quick work of the second button as well.
"Hey," Kotoko says, her voice surprisingly soft considering their current state. Naoki pauses when she leans up on her elbows and takes his face in her hands. She smiles happily at him and bites one side of her lower lip. "I love you, too."
Naoki looks at her. Hair already a mess, shirt half undone, skin glowing in different shades of pink, breathing shallow and stilted, full lips parted and bruised. He can't remember a time she's looked more beautiful.
"I know." He nods and surges up to kiss her again.