
Well, you don't lose someone's number just bc you get a new number these days. I would think its the first reason. He changed his number but never contacted Wooyeon probably bc they parted on an awkward note. Doyoon was a legal adult being confessed to by a minor, its not wrong of him to choose to put a distance between them. He knew Wooyeon went abroad for studies so he must have asked around may be, we don't know how they actually parted. And Doyoon hasn't gotten a drastic change in his appearance like Wooyeon so its clear for Doyoon than Wooyeon recognizes him but hasn't even brought it up. He confirmed its the same Wooyeon from his number and is simply letting Wooyeon take his time imo. Wooyeon thought Doyoon wouldn't keep his contact bc they weren't in contact. From Garam's attitude it doesn't look like he is a playboy, bc she did say he gets a lot of people who are into him join the club for him but she never said he dated anyone in the club which may have encouraged the behaviour. She also said he hates people sitting in his passenger seat, which is hard to avoid if you are dating someone. Sleeping around though is a different matter, but he doesn't come off as a playboy. He comes off as a rigid guy imo.

Read the entire novel here! So Dohyun does know who he is. After he quit tutoring he changed his number and removed his contacts. When Wooyeon called Dohyun and he looked down and saw his number he only saw a phone number, he remembered his number and everything.
However this isn’t the reason why he remembered, he actually truly didn’t recognize him when they met again. However Garam was right before Dohyun and told him that’s “Seon Wooyeon”. This is when he immediately knew it was him. The number only confirmed it.
And no…Dohyun is not a playboy. If you read the entire novel you will know. Let me know if you have any questions. I know the story like the back of my hand.

Read the entire novel. Dohyun changed his number. When he looked at his number he just remembered Wooyeon phone number. However he knew it was him from the beginning when Garam told Dohyun his name. So the next chapter when they went to the bar, Dohyun knew it was the Wooyeon he knew. Dohyun isn’t a playboy and it talks about how he dated other people but it didn’t last long and they just faded apart. Let me know if you have questions! I know everything about this story lol

Also what’s kinda crazy is the reason he quit his tutoring is because he was nervous about Wooyeon feelings. He started to feel strange about it, almost nervous that he could catch feelings too. Even Wooyeon mom noticed this and said he better take responsibility..which is crazy since Wooyeon was 14 and Dohyun was 18 . But he never thought of Wooyeon In a sexual way and even now that he does have feelings for him he doesn’t think of Wooyeon in a sexual way, only when they start to do something for the first time when Wooyeon was drunk.

Yep! I actually translated the rest myself. You might see my link around the internet
https://docs.google.com/document/d/1b_kftpLqutrwAkegiYIurjevRKQOtq9sNX5xfHxPFgk/edit
idk if im reading into this too much, but i think we can all assume that dohyun knows who wooyeon is. when wooyeon called dohyun’s phone so he could save wooyeon’s contact, a name appeared and dohyun smiled. its either, one, he has always had wooyeon’s contact in his phone even though dohyun got a new number, or two, dohyun is a playboy. i think its the latter.
i cant read korean and the text was really blurry so i couldnt read what was on the phone.i think that scene has some sort of significance cause we even got a panel dedicated to what dohyun saw on his phone