
I do believe Hangyum, the idol is the friend from high school.... and not the twin Hanwool we just saw on the plane.....
"the brown haired guy is the one-night-stand-ish" I am going to assume Hajin is referring to him in Chapter 18 when he lied about not being serious about another guy..
I am going to assume that the brown haired guy which is Han Jae.... is the Jaehee mention in Chapter 14... Sohyun's boyfriend.
http://www.mangago.zone/home/mangatopic/4979509/

Hey Sanchan....... I had wrote a message to someone and discovered something you may like to know.... I had to pull up chapter 16 and it was still up at the end after my message. I was looking at when Haeun was talking about Hajin break up with his girlfriend because she cheated. Haeun says "When Hajin found out his girlfriend was cheating on him. " and "In any case, what kind of woman was he dating, and how could she cheat on him of all people?"
After I noticed Haeun thought "Jahee, the selfish brat." I made a discovery with this....
First I would have to see the Korean version because Tapas may had mess this up. I put Jahee in google to see what gender the name would be..... Jahee does not come up with out baby name add on it. That is an African-Swahili name... boys name...... what is the real kicker here is that google asks Did you mean: jaehee for both inquiries.
As we know, Jaehee is the name, Sohyun's boyfriend (chapter 14). And Jae is all we can see with the one that looks like Hajin's ex in a flashback in (chapter 5)....
If she did think Jaehee, and Tapas put the wrong name... I will assume and supports us in what we think...... Han Jae... is Han Jaehee.. He had a serious relationship with Hajin, and Hajin caught him cheating. Now Jaehee is dating Sohyun. This explains the thumbnails a little better chapter 19-24.... The relationship he hid from Hangyum in Chapter 18 must be his relationship with Jaehee. well "Jahee" is too close... I bet an error on Tapas part.
If this true Haeun is covering up for Hajin and is talking about Jaehee that is in Chapter 5. So talking about your brothers ex boyfriends would be awkward to say to an idol that may not know his stylist sexual orientation (but he does. haha).
I have to see the Korean version because the English translations are messing up. I can not say this is true with seeing the Korean version but I can only assume. Because Lee Hangyum shorten his name is going by Lee Han in the Korean Version.
Following the story until now, my assumption is that.. The singer twin brother is the ex from high school and the brown haired guy is the one-night-stand-ish ... Or am I wrong...?? @0@