This reminds me of the Novel of Demian of Hermann Hesse... Talking about the id, ego and super ego. Hae-in is like Demian in the novel, the super ego, the perfection and ideal.
Both stories are portrayed similar with romantic moments but at the end the protagonist wants to overcome his ideal person, kisses him and says goodbye because now he is his own person.
Also it reminds me to Kaworu with Shinji in Evangelion. Kaworu being the self love and perfection and being the super ego of Shinji, repeatedly tells him that he loves him. Because that is the main goal of Shinji, accepting himself.
I always wanted to read a BL with an elite coed high school like Ouran Host Club, where there are festivals, chasing dreams and adventures with classmates, kind of old Shoujo school vibes. I have my hopes because the art is so good, love the eyes. Even the extras have a magical vibe.