https://www.dlsite.com/girls-pro/work/=/product_id/BJ578520.html As always, please support the artist and buy his works.
A night when I'm embraced by someone other than you
"---I'm having an affair. Not with the man I'm marrying, with my ex-boyfriend." ---Miku is getting married to her elite fiancé, Yuma, a month later. However, she has been hurt by Yuma's arrogance since she started living with him, and her heart has been exhausted. One day, Miku has to look for a job because of her family's situation, and she meets her ex-boyfriend Chihaya again by chance. Chihaya, who is still as kind and reliable as before, helps Miku to find a job. Then, she sees Yuma cheating on her outside while she is at work. When she is shocked, Chihaya sees this and says, "...I wouldn't have done that if I were you," and suddenly he kisses her passionately, making her melt! I can't do this, but I can't refuse....
@Coledas Ukgent There will be in the next chapters. This is an otome, i.e female-focused doujin, so they try to set in the mood and the plot first before getting to the sex scene