https://www.dlsite.com/maniax/work/=/product_id/RJ01345338.html
https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_477174/

[Synopsis]

The protagonist, Hayato Kinosaki, who worked in sales in Tokyo, quit his job after getting tired of the relationships in the city and later finds employment at a local bookstore.
His former classmate, Ikumi Kuramoto, works there and when he realizes that he is attracted to her unchanged inner self, he starts inviting her out to dinner and the distance between them gradually closes.
It doesn't take long for them to start dating.
He has no complaints about his boss at work and he has a beautiful girlfriend who doesn't say much.
He is excited and begins to focus on his work, thinking that starting his life over in his hometown was not a bad choice.
Savoring his happiness both in his private and public life, Kinosaki becomes addicted to the thrill of seeking a physical relationship with Ikumi at work.
She responds and begins to comply with his requests.
As a result, his actions are discovered by the store manager, Kojima and he ends up having a weakness.
Ikumi doesn't like him and is disgusted by the boss playing with her body but as she moans with an expression she's never shown to Kinosaki and has sex with her in ecstasy, she becomes excited
and the pleasure of serving him awakens her own perversion...

Base +28, Fofotron +26, nuts987 +13