King of the Frost by Elizabeth Frost

A castle in the sky.
A faerie king.
A changeling child.

Sounds like a fairytale in the making, right? Ayla might have agreed if she didn’t remember her parents throwing her to the humans. She’s little more than trash to the fae, which is why she’s happy to betray her old king.
Except, he spreads madness to everything he touches. Madness which feels right in her skin.
Ayla realizes she must choose between the safety of her new people, or the strange addiction spread from the king to her. A little crazy makes life worth living.