"Rules of Love" is a 2005 kdrama that kind of goes off the rails, as the main character thinks she slept with a guy she just met and he's telling her she has to take responsibility... the truth is quite different.

Jae Min is using Geun Young just to get a job with photographer Seo Jun, who her brother works with, but the naive girl believes his words and falls in love. Eventually, she finds out the truth and creates a break-up contract, making Jae Min stay with her until she gets over him. What happens next is the cliché of a romantic comedy, Jae Min falls in love with Geun Young and doesn't want to break up with her anymore, but at the same time, she's starting to like Seo Jun and so we have our love triangle. HAHAHA'

Choi Kang Hee is amazing, I really love her acting and, despite hating the character Jae Min, Shim Ji Ho's acting is really good, as is Kim Min Jong's.
It's a sweet story, it's about relationships, self-discovery and finding what love really is. If you like old kdramas, it's a good choice.