Choeseoneul Dahae Huhoehaseyo

For Olivia Madeleine, illegitimate daughter of a duke, her only hope of a better life away from her cold-hearted family is her betrothal to arrogant crown prince Leoford Franz. When the revelation of his tryst with another debutante comes as an unsurprising wake-up call, she has no choice but to barter for her freedom with Edwin Lowell Vikander, the ruthless, war-hardened Grand Duke of the north. As her dangerous dance with Edwin begins, Olivia seeks to leave her former fiancé with the coldest gift that vengeance can impart… A heart made bitter with regret.

(Source: WEBTOON)