The Sacred Beast Behemoth, Reincarnated as a Human With "Utimate Status", Accidentally Steals the Hero's Fiancée (The Princess)

I am a Behemoth, the most powerful being, who was reincarnated as a human for a certain reason. The day I was reincarnated, I ended up saving the life of an elf maiden. That night.. she asked me to have "sexual relations" with her..? And it turns out she is the nation's princess.. what should I do!? (Source: Hakusensha, translated)