Hooray for Love

Kang Jae Mi led a happy life with her parents, but by the time she was 19 years old, her father had an affair, and her parents soon divorced. Jae Mi promised her mother that she would never see her father again. Later, Jae Mi fell in love with Han Jung Soo and married.
3 years later, Jae Mi tries her best to make a happy family. She runs a restaurant with her husband and, for all intents and purposes, is happy. Jae Mi also believes her husband is happy. Due to her parents' divorce, Jae Mi is also firmly resolved that she will never divorce, but it turns out that Jung Soo is having an affair with another woman. Furthermore, his mistress becomes pregnant, and Jung Soo wants a divorce. On their 3rd anniversary, Jung Soo gifts airplane tickets for Guam to Jae Mi, her mother and aunt.
Byun Dong Woo is a lawyer who is supported by his mother. He has always been influenced by his mother and sister. Dong Woo always thought he wanted to be single for the rest of his life. Through a twist of fate, his sister's husband is also Jae Mi's father, Kang Hyung Do, which is unknown to all parties. To make his mom feel better, Dong Woo bought airplane tickets for Guam.
Both families head for Guam on vacation, unaware of the fated unions that are bound to occur. Meanwhile, while Jae Mi is away in Guam, her husband Jung-Soo carries out his plan to illegally file for divorce.
(Source: AsianWiki)