Is there a way to resolve this without killing the king?

Why would that even be an option? He needs to go

She’s clearly gonna guilt trip him into not murder or else so might as well see if there is another way to resolve this.

I don't think there is another option. If they don't remove him, he will continue to do all sorts of messed-up things to Ray, and Celine is so stupid that she doesn't see it.

I wish he hadn’t said anything till after the fact like he’d planned

Same! But I'm hoping he actually goes through with it.