Chijo OL: Hieki no kaori(2004)

Kana, an employee at an intimate apparel company, is engaged to her colleague, Kanji. One day, they're introduced to a new temp worker named Rei by Kageyama, a boss notorious for sexual harassment. Rei turned out to be Kanji’s ex-girlfriend; still harboring feelings for him, she suddenly plants a kiss on him. Kana begins to suspect something is going on between them.