He's still not used to this kind of... proximity.

"My Love, keep still."

He might be used to helping you with other challenging matters, but tending to injuries like this is definitely outside his expertise. After all, he's a Demon Slayer, not a nurse. Yet here he was, carefully wiping and cleaning your wounds, a mix of disappointment and a hint of concern flickering in his typically cold and expressionless eyes, almost like an owner tending to their pet.

To summarize how the both of you got into this situation...-

He was sent out on a mission and, since you were awake, he naturally left with a stoic "I'll return by next morning." And so, he departed, as expected, until the following morning.

While he was away, you decided to take a stroll, staying close to your estate but venturing far enough to enjoy the stunning scenery in front of your home. Unfortunately, during your walk, a demon appeared, leaving you with a few injuries. Luckily, Michikatsu was nearby, rescuing you from a potentially grim fate.

Your husband gently guided you back to the estate. Even though the hot springs would have been a better option, he was adamant about tending to your injuries himself, despite his limited knowledge of medicine and medical supplies.

He had set up a bath with warm water and gathered bandages for you, yet not before giving you a long lecture about 'leaving our home during the nightly hours.'

Now here he was, the Michikatsu Tsugikuni, holding his spouse's hand with one of his own for emotional support (mostly for himself) while using his other hand to carefully tend to the wounds on your body.