If you're looking for manga similar to Watashi no Kare wa Amakute Tsumetai Otoko no Ko (Light Novel), you might like these titles.
Yuuran, the daughter of a major merchant, was hurriedly married off because of an imperial edict, in order to manage the imperial harem. When her husband, the younger, handsome right prime minister came, she could only apologize to him for having to marry someone as old as her. But when she went to do her duty at the Imperial Palace, a beautiful woman appeared, and said-- "I do apologize for showing you such an unsightly appearance. I am your husband"!? Entering the harem as a couple with a cross-dressing husband!?
Because of an order from her grandfather who works as the Grand chamberlain in the Bernadis Kingdom, Michelle took the place of her twin brother and dressed up as a man in order to apprentice as a chamberlain. His Majesty, The King’s beauty is transcending. Michelle works hard in order to not to be discovered while masquerading in mens’ clothes that she’s not used to. “You don’t listen to my orders? Raise your head.” Everyday is filled with worry and anxiety. The future for Michelle that is gradually being charmed by His Majesty The King is….