Her Instruction Manual

Seung-ah, who has sadomasochistic tendencies, is brutally dumped by her adorable younger boyfriend, Min-woong. Five years later, Min-woong returns as the newest employee at the company where Seung-ah works. Now much more mature and attractive, he completely shakes her heart. Meanwhile, Ji-seok, her coworker, has been secretly in love with Seung-ah for years. And so begins the competition between the two men to win her heart…

Original Webtoon:
Toptoon, Anytoon, Lezhin