Kutabire Salarymen no Ore, 7nenburi ni Saikai shita Bishoujo JK to Dosei wo Hajimaru

From NU:

Amae Yuuya, an office worker in his third year of employment, is completely exhausted by the daily grind. Then, for the first time in seven years, Yuuya meets Aoi Shiratori, a girl eight years younger than him who used to live in his neighborhood. She had grown up to be a beautiful JK girl who was good at housework, and she said to him,

“Yuuya-kun, would you like to live with me under the premise of marriage?”

Aoi desperately wants to live with Yuuya, her first love. Yuuya, who is puzzled, agrees to live with Aoi as a guardian for the time being, but Aoi’s aggressive approach makes him very nervous inside.