They're actually both very intelligent so Idk why they lack so much when it comes to their...

It's not about communication, they are in a real predicament since both are in the right. The king can't leave the unstable throne empty and needs a heir to secure his power and a queen to maintain that said power when he is traveling but he loves Shin, he is his soulmate. When decisions are made someone is going to lose, Shin , the king or the kingdom.