This thread is ridiculous. This man may be all of things pp have accused him of, or he may not. There is not enough information here to make a judgment either way, yet here we are feeding op's insecurities.
In a private conversation with a friend he said that 'Korean chicks are hot.' So what? No woman has ever said that they're attracted to a particular nationality or type, when talking to a friend?
He liked some IG pictures of a singer-songwriter. She's got 2 million followers. I follow her, and there's nothing sordid about her account.
OP talks about how wonderful this man is and how well he treats her, so how have these two innocuous things trumped all of that?
OP - You shouldn't be reading his private messages. I couldn't live with the level of scrutiny you are placing on him. When you tell him that it's unacceptable to talk to friends about who you fancy, or who to follow on sm, you seek to control him unacceptably imo. You are making him feel like he has done something wrong when he has not.
If a woman posted to say that her dp was cross that she'd mentioned to a friend, in private messages, that she found Italian men very attractive, or that she shouldn't follow, I don't know, Jamie Dornan, on IG, mn would be telling her to get shot of him.
I'd ask your rl friends or family for advice before acting on the advice of mn.