Well, based on how the story pretty much shows it, Thalia is seen as an eyesore. Her existence is the very proof of the King's infidelity towards the late Empress. Even if the King loves Thalia's mom, it does not man that he would love his lover's children, even if they are his own as well.
i was wondering why is the king so indifferent toward thalia? doesnt he love her mother more than anything?