Anata de nai Dareka ni Dakareru Yoru

Overview

"I'm cheating... This isn't the person I'm planning to marry. He's my ex-boyfriend..." In one month, Miku is set to marry her fiancé, Yuma, but after deciding to live together before they officially tie the knot, she realizes that he may not be the kind person she thought he was. As his domineering attitude slowly causes her heart and mind to crumble away, she reunites with her ex-boyfriend, Chihaya, while searching for a job to support her family business. Still as gentle and dependable as he was in the past, Chihaya offers to help her find work. On one such day when Miku and Chihaya meet to discuss a job, they coincidentally witness her fiancé with another woman...! Seeing her shaken by this new revelation, Chihaya suddenly pulls her in for a hot, passionate kiss and tells her, "I would never cheat on you like him." Though she knows this is wrong, she is unable to push him away. (Source: MangaPlaza)

Source: AniList