I really liked this story and how it was written.
My mom went through some heavy traumas in her life and if she hadn't been brainwashed and become a christian (basically part of a cult) I believe she would be like the MC, she can't sleep alone or live for herself, there always has to be someone in her life. Anyway nowadays she's married...
In my interpretation, Jinwoo didn't stop loving Candy he was just depressed.
As someone already said in the comments, Candy hasn't changed his personality at all since he was a teenager and lives as an artist. Jinwoo has already changed and matured more, He works in an office, which, knowing Asia, must demand a lot from him. A 10-year relationship without any changes and still contributing socially as an adult is quite tiring. Idk I believe that his relationship became a struggle due to the little free time he had, and as a result he was always tired simply wishing for a break from everything.
With this manga I discovered that I have philophobia, I even mentioned it to my mother and she was surprised that it had a name and completely agreed.
Anyway 9/10