18 Kin Sound Novel Game Natsuko

Shou-kun was a 20-year-old freelancer in love for the first time.
The girl of his affections also seemed to like him. But due to his lifestyle
they couldn't be together, she said. Shou-kun loved her... but not
enough to give up his single life, get married, and have a kid...

Shaken by the lost chance, Shou-kun began to work hard and save money.
Years passed, and one day he met the girl of his affections again...

[From DLsite English]