Hitozuma Matching Appli: Harem dekiru Junai Mansion

Chihiro, his childhood friend, has always been like an older sister to him and is the woman Yuuto admires. She is already married, so he thinks he has to give up, but since they live in apartments next to each other, there are a lot of temptations. Chihiro is always defenseless and her actions are bold, so she always confuses Yuuto with her charm. The latest app "for married women'' that was recommended to him is a dating site that matches with beautiful women in the neighborhood for sex purposes. Prompted by Chihiro, Yuuto ends up repeating his enchanting experience...

(Source: Otona Bunko, translated)