His Until Dawn by Fionn Jameson

Rika is determined to keep love and lust separate. And that means making sure her relationship with Nobuki remains strictly physical, no matter how much her family wants her to settle down. But with her heart set on causing trouble, Rika is forced to confront the fact that maybe, just maybe, she might have caught feelings for her boss. Now more than ever, she has to keep their relationship secret, or else risk losing her job and Nobuki entirely.

And while Rika fights to preserve life as she knows it, both her sister and best friend do their best to ensure that Rika is living as they think she should, whether that means setting her up with another man or encouraging her to fight for Nobuki’s heart.
But life only gets more complicated when rumors begin to circulate the company, rumors with the potential to reveal the true nature of the couple’s connection. And if that information gets out, there’s no amount of bargaining that will save them.