@Rheia "Maybe TJ should have respected Ian's decision to take drugs and just watch his loved one die?" 
I think that if Ian had known he would end up killing people and becoming a monster for Tj's sake, he would have preferred to die of an overdose right then and there. And the fact that after everything Ian went through with his addiction Tj still makes him deliver drugs it's pretty twisted. 

I won't keep trying to explain to you what I'm pretty sure you already know. But since you like to quote the author. Let me share this:
"Ian tries to leave his past behind and turn a new leaf. For the first time he learns what it's like to live an ordinary life but his old friend and lover Tj, REFUSES TO LET HIM GO." The author's words, not mine. (Tappytoon interview) And when the manhwa was released, she introduced Tj's character with the # 집착공 (OBSESSED TOP) 
Apparently it was lost on you how Tj's been presented time and time again as an obstacle preventing Ian from achieving the life he wants and deserves. So yeah I don't think Tj is good for Ian. That's what I was trying to say in my original post, but somehow you turned it into something else.

@Rheia Look buddy, first you need to chill, there's no need to be rude and get so worked up over fictional characters. No one is talking about villains here, you're overreacting. 
And let me tell you something, it's very frustrating talking to you because you keep making things up to fit your narrative. And you won't even acknowledge the basics. 

"Jamie is trying to get to Ian through Chris and Joseph."
How come you don't understand that the end goal is Tj not Ian. If Tj wasn't in the picture no one would be after Ian three years after he left the gang. Tj's the one putting him in danger by keeping him tied to him. 

"TJ never liked that Ian taking part in such a dangerous sport." 
Again, it wasn't Tj's place to decide, he felt he had the right to manage Ian's life and interfere in his future. 
And riding motorcycles is nowhere near as dangerous as being a gang member where the chances of getting murdered, as we've seen, are extremely high. 

"TJ understood how much Ian blamed himself for this, so he asked to give Ian a short sentence, which was later reduced."
You just made that up, Ian's sentence was never reduced, he served two years, it's in his bio. Maybe you said that to make it look less serious. But even if it was less time, it was not Tj's place to decide what punishment Ian should get and he had no right to send him to the most dangerous place someone like Ian could be, prison, where it's very easy to place a hit. In fact Ian had to pay for protection himself not to get murdered.

@Rheia "it is logical that TJ wants to tie him to himself so that he has the opportunity to protect Ian."
The only reason Ian is in danger is because he's tied to Tj. Jamie is not interested in Ian, he wants to use him to get to Tj. And Ian isn't a princess that needs protection, he was a boss of a dangerous gang, a prodigy and when his subordinate tried to kill him we saw that he's more than capable of protecting himself. 

" If we talk about the situation with money, then nothing is known yet." 
Tj: he'll find it hard to survive on clean work, I'll tie him down with money. 
Jason: he'll kill himself trying to pay. 
Tj: I know, I'm just buying time. 
Tj thought Ian would break and come back to the gang, he's still expecting that. 

"The accusation that TJ has relationships with women is completely incomprehensible to me" 
(Jason: I heard you broke up with that woman.)
We also saw another woman leaving his hotel room smelling like him. 

Look, buddy, I could go on, but I can't explain everything to you. I strongly recommend you to reread wetsand so you can get a better understanding of the big picture.

@Rheia "his subordinates followed Ian because Jamie Lee is trying to harm him."
They discovered Jamie's plan now, that's why Chiwoon assigned protection, but in the first chapters we saw that Tj did it to keep tabs on what Ian was doing. We even saw Tj sitting in his car spying on him. If he had protection back then, they would have seen him meeting with the fake ID guy. 

"thanks to TJ’s influence no one in the gang touches Ian, although they consider him a traitor."
The only one that considers Ian a traitor is Yangji, we've seen how the other members (Jason, Chiwoon, Daniel, etc) not only respect Ian, they care about him. 

"The hired men were supposed to just restrain him, but a fight broke out"
Don't you think a guy like Ian would put up a fight? How do you think they were supposed to restrain him? 

"TJ's parents died in a car accident, so of course he was scared that his loved one could repeat their fate."
Ian had been riding as an amateur for quite some time but Tj only decided to stop him when Ian had the chance to LEAVE and become a pro. If he was afraid of Ian riding he wouldn't be building a garage for motorcycles in the new house. 

"Prison is obviously the only way to prevent a kind person like Ian from doing something to himself out of unbearable guilt." 
Tj never respected Ian's decision to leave the gang, he wants him back in, even though he saw how unbearable it was for him.

"We see that Tj does not restrict Ian's freedom and gives him easy work so that Ian has money to live on."
Hiring thugs to forcefully stop him from competing, sending him to prison, putting an enormous debt on him, etc, is restricting his freedom. 
Ian has no money to live on because he's killing himself to pay the debt Tj put on him.