OK, this chapter gives me serious concerns about the relationship between Navier and Heinley.
Namely, Heinley is the king of a kingdom that is secretly planning to invade and destroy Navier's homeland. And this is a plan that the western kingdom has been secretly executing for some time, while the eastern empire remains on friendly relations with them and Navier clearly sees the western kingdom as a friend and has no clue that this war is coming. Regardless of how sweetly Heinley courts Navier, this is a betrayal worse than cheating on her with another woman.
And for those who would justify Heinley's actions because Sovieshtu has cheated on Navier, that's the narrative of the story tricking you. If a scenario was presented to you where a foreign dictator seduced the wife of the leader of your country after your leader had an affair, and then that dictator subsequently invaded and conquered your nation with your country's former first lady at his side, you'd call him a backstabbing snake, and her a traitor. The fact that this would be payback for her husband cheating on her would be seen as in no way justifying war and treachery.
Basically, Heinley is plotting a betrayal of Navier far worse than Sovieshtu.