Cast Off by Enola M. Douglas

An arranged marriage. A fragile alliance. A love neither thought possible.

Omega Princess JingYi of Xûen-Sarai has always lived in the shadows—unseen, unwanted, valued only for her rare healing gifts. Sent to wed a powerful Alpha lord in a distant kingdom, she hopes the marriage will finally bring her freedom and dignity.
Alpha Lord Alexander Wulfbane expects a flawless Omega bride to restore his disgraced House. But almost as soon as the vows are spoken, their marriage begins to fray. She is nothing like the perfect wife he imagined, and disappointment quickly turns their alliance cold.
Beyond the strained diplomacy and wary distance in their marriage bed, a greater danger looms: Omegas are vanishing across the Nine Kingdoms, and whispers of a forbidden substance threaten to topple every throne. To survive the gathering storm, JingYi and Alexander must turn their reluctant match into something stronger—trust, partnership, and a passion neither expected.
She’s not the bride he wanted. He was never meant to be her hero. But when the realm itself turns against them, standing together may be their only hope.