My Botched Life: Take Two [VertiComix]

Ai Suzuki was a failure at work, a burden on the company, and had no friends... the only person who loved her was her boss, Tatsuro. To society, their relationship was an immoral affair, but to her, it was true love. One day, driven by loneliness, Ai goes to see Tatsuro, only to find another woman with him. It turns out Tatsuro had other mistresses! After being stabbed by the other mistress, Ai wakes up in a parallel world, reborn as a successful, confident, and highly capable version of herself...?!