jiheon is the annoying possessive type my god and extra delulu. He's so convinced Wooju has no life outside of himself, so of course it's insane for him to have other interests or a romantic life. Like you seemingly abandoned him for 2-3 years! Jiheon should be glad that he's still on a besties level.
also i will be so mad if the reasoning behind jiheon being so secretive about his life to Wooju is something unrelated to the kidnapping incident or any other plot point.