Around the start of season 2, Si-eon’s ex comes into the picture still kinda in love with Si-eon and tells Namwoo to break up with him because he’s bad news. (Nothing comes of it but you’ll see around the end what happens to the rival). Betrayal is there but not in a cheating sense more in a way that Si-eon lied to Namwoo. As in a sense that Si-eon didn’t mention that he knows Namwoo’s sister. They also both lied to her about their relationship to his sister because of the age gap. But they never had a thing where they cheated on each other, instead just that one of them was incapable of loving the other for a bit.
The only part that I can think of that’s a bit iffy is probably just the first chapter since towards the end of the chapter Namwoo wakes up with his bed covered in cash. You’ll see why if you read it.
Now that comments are back I just wanna say this is probably one of the BEST series I’ve read. Like honestly never seen a relationship with a good ass dynamic. Is the age gap kinda like “oh” YES but god damn I fucking love the development of this. It doesn’t have Sieon being a crazy fucking maniac and it doesn’t have Namwoo as some damsel in distress. Can’t say anything else or I will spoil it but holy fucking shit do I love this.