"I've decided. I'm going to spoil you rotten!" Kensuke, an older student whom Tamaki had admired since high school, moves into the apartment next to hers. Kensuke had become a successful CEO of an IT company and acquired a huge fortune, moving up in the world. In order to protect Tamaki, a magnet for useless men who is being harassed by her ex-boyfriend, Kensuke decides to pretend to be her boyfriend! In exchange, Tamaki must clean up his messy apartment. Although it was only supposed to be a pretense, Tamaki is flustered by the older man's gentle protection... (Source: BisouBisou Comics)

After her childhood friend, whom she thought was her boyfriend, decided to marry someone else, Haruka eagerly began a marriage search of her own. Haruka fell for Eisetsu Amazawa, the handsome calligraphy instructor who saved her from harassment at a calligraphy mixer, and decided to attend his calligraphy class. One day, Haruka accidentally fell down and touched lips with Amazawa, for the first kiss in her life! She was upset about the accidental kiss, until Amazawa confided that he has never been with a woman before either....... (Source: Takeshobo, translated)

The summer of my freshman year of college---18 years old, I married my first love, my brother's best friend. Shiori, who lost her family in an accident, married her brother's best friend, Takumi Nakazawa under false pretenses, but she still had feelings for him. On their third wedding anniversary, just as Shiori makes up her mind to tell Takumi how she feels about him, Takumi declares, "Let's get a divorce. Shiori tries to avoid divorce, but she fails at every attempt, and even witnesses her husband alone with a woman...?

https://www.cmoa.jp/title/321286/

https://www.cmoa.jp/title/311504/