What did he mean by "giving up"

okay so here's my theory. sunny made some sort of deal with moony but doesn't know it's moony. now moony and his owner (Jin is not human, he's only taking up a human form) are looking for who sunny made a deal with, i'm assuming for peculiar reasons. probably to assassinate or exile him. but when Jin found Chinwoo he started liking him. now that there's no hope of them being together Jin is "giving up" the plan of looking for sunnys dealer. he even lied to moony saying he didn't find him.