Changing Partners (2007)

Young-joon and So-yeo are a young couple with their marriage relatively stable. On a day their mutual friend opens a wine bar, they come across Min-jae and Yu-na, a couple quite the opposite of themselves. After a trade of talks, Young-joon becomes a client of fashion consultant Yu-na, while hotelier Min-jae agrees to help So-yeo book a hotel for her Hong Kong business trip. So-yeo meets Min-jae by chance in Hong Kong, while Young-joon trades suggestive remarks with Yu-na who visits him on a consulting session. That night, the four of them find in the other partner what had been missing in their respective marriages…