
Jooin has the right to ask the questions he asked Cain, because when we like someone it’s important to know what their life’s like and Cain not telling him just keeps making Jooin insecure, specially after all he went through with Yahwi. He just wants to feel reassured.
The only thing that makes me a little sad is the way he said all of that, because Cain always treated Jooin with care and is always worried about him, sensing every time something’s wrong and Jooin somehow can’t feel when something’s wrong with Cain not even after the fact he haven’t been calling Jooin in a while and is now saying he just got a new number… I just want to see Cain’s background story.

You know, when you love someone, you get hurt when they don't tell you things. Or you feel like they don't trust you enough to share their worries with you.
I totally get that Cain is trying to fix things on his own so that he does not worry Jooin so much.
By reading your comment, I guess, Jooin was acting like a child not knowing how to read the room vibe. I might be right.
What Cain will need to master on his end is "not to run away from Jooin". Because he keeps on running away from him every time Jooin gets close to him. It feels like he is worried that Jooin won't look at him the same way when he finds out what has been happening to him.
Well, now enter COMMUNICATION...
Bro, Cain wouldn't tell jooin that his family beat him up because he wants to be with jooin. He wouldnt want jooin to feel guilty or worried or bad about that. He's trying to protect him as he always has. I get you're upset, Jooin, but you didnt have to blow up on him especially when you were emotional with yahwi. I'm so fricken annoyed