tj ian and Jamie all of them were working under street thug mr. jang to make their end meet. later, they met jason , k35 gang leader who had his eyes on tj for a long time he sees potential in tj as his right hand man so he wants him to join the gang but tj has no interest in joining gang until he saw ian was getting exploited by David Kim and other rich scums but tj couldn't do anything about it .Now this is the time when tj started to think about Jason's offer in one condition tj has to kill mr. jang . so he went to the location where jang holding ian hostage threatening to harm him because David kim is jang's customer and ian completely pissed them off by breaking free from his addiction. Now upon reaching the location tj had no idea ian will be there too as it's purely coincidence. so seeing ian being tied up he lost his shit so instead of just killing him swiftly with a knife that jason gave ,he beat the shit out of mr.jang with his bare hands.
now during the struggle tj got his face slashed and seeing ian looked all concerned and guilty about him killing a person and getting involved with gangsters is when tj started to wrongly believe banking on ian's guilt is the only way to keep him by his side.
in short he was guilt tripping ian the whole time by keeping his scar because of his abandonment issue little did he know ian was already in love with him .

Man someone explain ch 57 to me know