Kichin (2009)

Kichin: Today is Mo-rae and Sang-in's one-year wedding anniversary. After a busy morning preparing for the celebration, Mo-rae goes to an art gallery to find a gift for Sang-in. At the gallery, she meets a complete stranger and the two unexpectedly have sex. Mo-rae returns home feeling anxious and guilty about the incident and cannot help but confess it to Sang-in. That night, a visitor arrives at their house; Du-rae, who came from Paris to help Sang-in with his new business. To Mo-rae's shock, he is the man from the gallery. He temporarily lives with the couple in their house and a risky love triangle begins.