I think that the way they scripted the history in the show was way better than in the webtoon. In the webtoon after Yumi and Babi started dating again it had an episode of a personification of Babi's rings that the rings talked about how Babi was gonna propose to Yumi then the next episode there was a timeskip and Yumi already had broken off with Babi (with now explanation why they ended their relationship and how time has passed). Then some episodes showed how Babi was swayed by Da Eun and admitted that he liked her and thought that she was cute (it was him talked to himself, not his cells like in the drama) and when Da Eun called him in the middle of the night he answered the call (if I remember correctly) and later they got married and had kids. Also Babi later admitted that he only liked Yumi because she was in love with Wung, he said that she had "a glow" and that his currently girlfriend didn't have so he is a total jerk in the webtoon but my theory is that the webtoon's author wanted that Yumi ended up together with Babi but he recieved backslash of the fans (because Babi is a jerk) so he just "erased" everything with the timeskip lol

Spoiler: I think that the webtoon went downhill after that stupid timeskip, and Soonrok Shin was just some random guy that the webtoon's author made up in the last minute to be Yumi's husband, because he was really bland and even the villain that the author made in the last episodes was really stupid compared to Ruby, Sia and Dae Un. Also the ending was totally unexpected because Yumi and Soonrok went to a trip then he proposed to her then they good married, end [??]

(For people that didn't read the webtoon the author stated in an after ending episode that he planned to end the story on episode 55 and this episode was after Yumi and Wung went to a date in the park, so the rest of the story wasn't planned too).

So responding that question, they made Yumi break up with Babi because they wanted to follow the webtoon's story. Which I liked that they broke off because I hated Babi and I don't care if he is less of a jerk on the drama lol

“I do understand you but the main thing was that yumi never got swayed by anyone while being in  a committed relationship.”

I think people are truly missing out the most important thing, just because Yumi’s cells didn’t have an earthquake, what Yumi did was way worst than Babi. In Christmas Eve, all she can think of is her ex who she worries he will be cold and rushed out of the door during a date without even consideration her current boyfriend once. She met with Woong in the hospital, having her in her heart’s ranking, missing the old days, refusing to leave and insisted to buy him clothes when he doesn’t have to, constantly meeting with her ex who is actively pursuing her, laughed when her ex bad mouthing her boyfriend, going to meet him even when she’s sick and turned down Babi.

You must be joking if this is not swayed. 

Woong to this date still think Yumi will love him if he had money. That’s what he thinks of her. Does he even know who Yumi as a person? He lied to Yumi about his ex-crush, disrespectful towards Babi, pursuing someone else’s girlfriend? Buying the books and writing reviews are also so disrespectful for Yumi as a writer and discredit her skills. 

I hate shows like this that make people roof for Yumi and Woong when they are so toxic and self centered yet glorified their actions as self love and “not swayed”. All their actions are swayed but just because the original material pinned Babi as the “swayed” one, suddenly he’s the bad guy and the other twos are saints. 

I really don’t like how writers creating this kind of toxic views and making viewers believe this is the right moral value. You don’t have to like Babi as a character, but there’s no way to justify what Yumi and Woong did that’s way worst than Babi.

ikr!!!!!!!!!!! its like some indian drama shit where the story just goes on and on and on. it goe son till there's no essence left in the story or the characters.