Single Wife(2017)

Original title: 싱글 와이프

A woman prepares for her remarriage to the perfect man, a second generation chaebol, but in the midst of those proceedings, she realizes that her divorce from her ex was never legally finalized. She has to lead a double life, leading both men on until things are settled. However, her ex-husband-to be is involved in an accident and develops amnesia, completely forgetting that they're no longer a married couple.