Crown of Ellova, Vol. 1 by Sienna Harlow

Falling for a mortal is forged in heartbreak.

On each full moon, half-fae Izadella sneaks out of Ellova, the beautiful fae realm she calls home, and travels to the miserable mortal kingdom. There she sells her magically made jewelry to the wealthy courtiers who attend a bazaar in honor of the dying mortal king who wears the stolen fae crown—the crown Izadella’s ancestor forged, which holds unfathomable magic and can only be removed at death. During each visit to the mortal realm, she falls deeper for the man she can never be with: Leon, the king’s personal healer.
When Izadella is forced to wear the fae crown, awakening lost magic, she must bring Leon back to the realm of Ellova, a luxurious place where mortals are forbidden, and their feelings for each other continue to blossom.
Together with Izadella’s best friend, Nueena, the heir to Ellova’s throne, they must create a life-saving elixir to save those suffering in the mortal realm, where the stolen fae crown has slowly destroyed the kingdom.

No matter how much Izadella and Leon long to be together, time is running out. Leon cannot stay in the fae world; the magic will drive him to madness. Izadella cannot join him in the mortal realm as she will die without her magic. Will she love him only to lose him, or lose him before she has the chance to love him?