Oyasumi no Kiss wo Konya mo: Toshishita-kun to Dekiai Roomshare

When her friend decided to get married, Shiho needed to find a new roommate in a hurry. She was told that her childhood friend Yuri, who is seven years younger than her, is looking for a new place to live. It turns out that Yuri has had a crush on Shiho since he was a child... A doting cohabitation romance between a devoted younger man and an innocent around-thirty lady.

(Source: Kodansha, translated)