I get having low self-esteem, but it doesn't help when the other guy questions every time he goes out with a friend. He's allowed to have a life. If he has legit concerns about a particular friend, then he can bring that up, but it all needs to be talked about.
Yeah it's super common in BL for MLs to be jealous or suspicious of every single friend/person their partner interacts with and IRL that's such a red flag. Jiwon's given him no reason NOT to trust him.
I get having low self-esteem, but it doesn't help when the other guy questions every time he goes out with a friend. He's allowed to have a life. If he has legit concerns about a particular friend, then he can bring that up, but it all needs to be talked about.