Yeah same. I feel like it's part of his character. The whole time I was thinking, he needs therapy, to fix his self esteem and solve through his traumas. Also develop his own life, everything depended on if FL would be in his life (whether he had a job, whether he would make an effort at school etc.). Man needs to start investing on his own feelings, hobbies and goals (not in a manosphere type of way lmao).
I think it was clear after some chapters where he said he got over the depression after high school. I think he's just timid by nature and obviously meeting those bullies again later resurfaced some of the trauma. Also to make things worse he was hiding the truth from FL.
The main issue was there relationship which later got fixed and he's doing good in his field. Also I think his relationship with his family is alright, the parents are just divorced. But yeah I felt something was missing but the bullies basically destroyed themselves it wasn't shown directly. They could give us some but they decided to focus on sex scenes ╮( ̄▽ ̄)╭

I don't get why people hate on fl but I just want to say that I hate how at the end nothing for him really got solved.
Like yeah now he's happy and has the love of his live by his side but everything that he has now can easily break apart if he's not with her.
He has no friends, there is no resolution regarding his relationship with his parents and most important he still has low self esteem.