I think you need to keep in mind how the relationship started, and the fact that Heejae was practically his soulmate also garam was in America with him for 4 whole years he invested so much of his time and energy and soul just to be with this old geezer and for him to take him seriously, and then his piano became so insanely intertwined with Heejae i’m surprised he’s not killing himself right now although this is close enough
Having a broken heart and being treated cruelly by a loved one affects the sense of self-worth, leading to low self-esteem too. This is compounded by the weight of memories and significant life experiences, especially in a long-term relationship that was deeply intertwined with other stuff, like piano rn. It is like having someone be your entire world, only to then act as if you had never met... After all, just as there are adults who still carry trauma from their parents, there is also romantic relationships trauma lol
Also the ego of being the only one who “truly” understood Heejae and his funk ass music there’s just so much and it so sad cause the two men he ended dating were a demon and the anti Christ itself like garam should have been at the club bumping tits for ass but instead he got sent to hell
Heejae really sucked the soul out of poor garam what a monster on a second note does love and romantic relationships really take such a toll on a person I can't really imagine being so emotionally dependent on other person (maybe I am borderline aromatic idk)