Young Do and Eun Sang eat at a noodle place. He confirms from her that she will be with Tan despite Daddy Kim's objections. He dumps her, and while Eun Sang wants to keep their friendship, he rejects it. He tells her she's his first love, but they're done.
Even if Young Do is a bit harsh to Eun Sang in this scene, I'm proud of him. I like a character who realizes what is essentially best for him, even if it means ending a friendship. It's a one-sided love, and the best way to get over it, is to remove oneself from it completely.