There was two main pairings in this story, the boss and one of his subordinates and the boss' secretary with...someone else (can't remember)

I remember the secretary's love story, his partner was calm and like the perfect man for him. Then the last chapter (the extra?) the secretary bought chocolate for his boss and the boss lover but his partner misunderstood (?) = =;; The secretary had glasses and black hair if that helps...;;

That's Keep Out (KISARAGI Hirotaka) if I'm not mistaken...

Yesss TTuTT thank you !