It Wasn't Love at First Sight

Eun-Jae Seo, a not-so-fortunate member of a wealthy conglomerate family, goes on a blind date with Si-U Yun, whom her grandfather arranged for her to marry. Initially wary of Si-U due to his bad reputation, Eun-Jae starts warming up to him as Si-U confesses he fell in love with her at first sight. She ends up falling deeply in love with him. The two seem to be a happy couple, until Si-U begins to reveal his secrets to her after their wedding.

(Source: WEBTOON, edited)