Nekokaburi no Koiwazurai

Izumi Akira, who works in the design department, is secretly dating Azuma Ryouji, a handsome man famous within the company for being the ace of the sales department. Although the relationship seems to be going well, Akira has a secret he can never reveal. That is, he hides his nature and pretends to be someone else to match Ryouji's type!
But one day, by a strange coincidence, he ends up staying at Ryouji's apartment for a while and that means, he has to pretend to be someone he's not 24 hours a day!

(Source: Core Magazine, translated)

Note: Includes one extra chapter.