If the drama followed the webtoon then we'd get a whole ep, if not two, focused on the villains. I don't know how the webnovel proceeds, but it's a good thing the focus is on KJW now that Yura's in the picture.
I've seen the ML in other dramas and he can def depict an obsessed lover, second to none. Here though the script feels weak. I'm on ep19 and I don't feel their chemistry. Maybe he doesn't click with the FL.
Unpopular opinion: I actually like the fact that they paused the chef and sister's romance. I'd rather have the promise of it at the end of the series than have it rushed bc everyone must have a happy ending. Also the guy needs some healing time. He literally confessed on their first meeting after years, that is some serious repressed emotion. Not to mention the sister played the matchmaker.
After lots of consideration I came to the conclusion that Yoora's appearance is justified. She was hinted at sometime in the beginning, she was mentioned in the webnovel as per posts and it makes the ML real. What I didn't like in the webtoon was the ML's angelic intervention in everything. He was just a means to an end. Now he's here, imperfect, insecure, scared, with a wacko past of his own, doing everything he can to protect the FL, an FL who was a pushover all her life and doesn't know how to navigate life. Yes, the excuse was lame, I'd have preferred a confused "I can't process all this, let me be", but at the same time she's always been duped and used and gaslighted so the trauma makes sense. And let's not forget she came back to save her future. He was never in the picture, whereas she was always in his heart. He had years of loving her, she had only fear of her husband.