The Poison Princess never had ANY romantic feelings for anyone besides "the one". Empathy and kindness is what she needed. In a place devoid of it. That is why she was so attached to dear Shicca and curious towards Kait. They expressed emotion, they socialised with her, they empathise and treated her kindly. They treated her like a human being. Not a monster, a tool or sexual object. Certain individuals never treated her that way. What they "felt" was more about themselves and their needs and not hers.
These are broken people (teens) twisted and controlled by the choices and actions of the adults around them. The King had his good points but he was not a good father. His final actions completely destroyed his family. He abandoned them to madness, debilitating and isolating loneliness piled atop of the heavy heavy burden of running a country. As King he broke his promise to his people and his allies. By abandoning all his responsibilities he kick-started all the damage that was to come. Hell, his actions as a soldier during the Coup had long lasting consequences. Even the Old Man's (traitor) actions created future problems. The Diviner added to this trauma with her bullshit "prophecy". All it did was haunt/stress these children with cruel meaningless labels that pushed them toward making "heavy" burdensome choices. It had nothing to do with cursed children. Also the Diviner didn't give two shits about the previous royalty (responsible for many things) who took the water away from other kingdoms causing a WAR. Where was the prophecy for THAT! She made me so angry.
This is a tragic story about damaged tortured people trying to survive an ugly twisted life that they were either dragged or born into the best way they can with a bittersweet ending.