Seiryaku Kekkon Shita Hazu no Moto Koibito (Gen Joushi) ni Fukuen wo Semarareteimasu

Her ex-boyfriend, who she broke up with due to differences in social status, shows up as her boss!? A Cinderella love story of adults, with secrets to protect and true feelings...!

Wendy's ex-boyfriend, Dennis, who was supposed to inherit the viscounty in place of his brother who passed away suddenly, appears as her boss after she has been transferred to a position as a royal civil servant. While bewildered by Dennis, who is still as kind and protective as he was three years ago, Wendy, aware of her position, tries to distance herself from him. But to begin with, Wendy has a huge secret that she must absolutely hide from Dennis...

(Source: Kadokawa, translated)