This is a flawed premise; it presumes that romance is something they section off, that exists in some parts of their life and not others, and this is not the case. One of the things that surprises Kaoru the most about her marriage to Kenshin, in fact, is how much love is involved - not that she thought he didn’t love her (how could she, after all that had happened?), but she’s heard from other women what marriage can be like - that it’s work, that it’s hard and dry and men change, afterward - women, too - but you carry on.
And given how reserved he is, she hadn’t really expected much to change, and she’d expected that those changes that did happen would be small, contained to private moments. And it’s true that he’s not much more demonstrative in public than he ever was, but…
When she wakes up most mornings, there’s a cup of tea waiting by her bed, and when she pads into the kitchen (Yahiko will be along soon, but not yet; now the morning is still and new and theirs) he somehow always knows she’s coming and turns as she enters, smiling. At first she wasn’t quite sure of herself, but as time passes she stops hesitating and steps up to kiss him, softly; he kisses her back and presses his forehead to hers, whispering good morning.
Their days pass as days always do, training and laundry and errands to run, but she knows, now, when he’s watching her (I was always watching you, he told her once, shyly, I just never let you know) and she watches back, greedy for the lean grace of his form the way he is for the hard curves of hers. He knows when she’s watching, too, and every now and then their eyes meet, bright with love and wanting.
(I was watching you too, she’d confessed back, and he’d hugged her close and smiled.)
They eat lunch together, when they can, and their hands twine briefly together when they do.
Dinner is variable: home alone, home with friends, home at a friend’s, the Akabeko… what never changes is that they sit together, knees touching even as their upper bodies stay politely apart, and sometimes his hand will stroke her lower back, or her fingers will trace the knobs of his spine, and everyone pretends, politely, not to notice.
(there’s a clique of women in the market with bitter lips like lemons who take great pleasure in watching them and waiting for Kaoru’s happiness to end, for the day that she starts walking three steps behind as an obedient wife should. It never comes; the women click their tongues and decide that she’s a harridan, but no one cares what they have to say)
After dinner they sit together, drinking tea, and sometimes they talk and sometimes they don’t, but always, eventually, they kiss - soft and sweet and growing fiercer, tasting tea on each other’s lips. Sometimes they make love, and sometimes they only kiss, but always they stumble and tug each other into their bedroom, into their shared bed, and they drift off to sleep entangled in one another, his head tucked close in the curve of her neck.