Queen of Legends by Frost Kay

Her barbarian prince promised Wren the world, and she left him in the dead of the night.

With nowhere to go and price on her head, Wren goes into hiding and joins forces with the Kingdom of Myths to destroy the corrupt elf king and reclaim her kingdom, but it comes with a price.
Killing her husband.
Prince Arrik swore to never fall in love, let alone with a human with vengeance in her eyes and fire in her soul. Yet, despite all his well made plans, he can’t seem to let her go. Even if it means revealing his secrets to secure his queen and crush his father.
As a twist of fate throws Wren back into the clutches of her devilish husband, she much forge a path forward that could lead to heartbreak, blood, or redemption.