Next Door Husband and Wife

Eun-ji and Seung-ho, Seong-sik and Joo-ran move into a neighborhood at similar times. Eun-ji is lonely because of her husband's frequent late-nights and Seong-sik takes care of the house while his wife works.
One day, Seong-sik goes over to Eun-ji's house to return a package but end up drinking wine with her. Seong-sik drunkenly kisses Eun-ji and the two spend a night in each others' arms. They continue to meet secretly like that and one day lie to their husband and wife and leave on a trip together. However, Seong-sik returns home because his pipes have burst and Eun-ji witnesses her husband and the woman next door, Joo-ran in bed together.
A few months later, Seong-sik, Eun-ji, Seung-ho and Joo-ran run into each other but with different partners... Are you living with the one you love?