It said the secretary is the king's lover right? Thats true right
No, he has a mother. Mifune was the Kings lover even before he married Shou's mother. Shou got caught in his parents drama and it made him not want to fall in love because it may hurt his lover and his future partner that would be chosen by the predecessor. The king and his wife split so now he just has Mifune as his lover. So it's more like Mifune is Shou's stepmother
I would die in happiness if the author (?) made them have their own babies*adoption or smtg i dun care* gosh IM HAPPPPPYYYYY!!! THANK YOUUUUUUUUUU ( ̄ε(# ̄)Σ