After Bahamut confesses her feelings to the King, the king reciprocates and they get married. Shortly after, due to growing pressure from his new wife, the king goes public with everything he had been keeping a secret: His first child – Damian, the fact that Bahamut is a dragon*, and that he has remarried to her.
The country is understanding, and not even annoyed. They sympathise with their reasons for secrecy, and appreciate the honesty.
*Bahamut – along with most metallic dragons – donned a humanoid form with their polymorph ability before interracting with the humanoids. Most have already revealed their true forms, to generally positive reactions. It occasionally caused controversy, but was eventually accepted.