3. The structural wound
Both characters operate from versions of the same wound with different shapes.
Rachel's version: I have to earn love through performance. If I stop performing, I will be nothing. Her Broadway ambition is not separate from her fear — it is the fear made into a plan. She does not know how to be loved for being small and quiet because she has never been allowed to try. With Finn she occasionally stops performing. That is what makes him irreplaceable.
Finn's version: I am not smart enough, driven enough, or clear enough about my future to deserve what I want. He knows he loves Rachel. He does not always know if he can be what she needs. Lima is safe. New York is what Rachel becomes. His uncertainty about whether he belongs in her world is the fic's central engine.
Finn's father wound (load-bearing in fic): Finn was told for most of his life that his father died a hero in the Gulf War. In Season 2, he learns his father was discharged for drug use and later died a civilian — and that his mother had lied to him about it for years. This is not backstory. It is the reason Finn builds himself around reliability. He is terrified of being his father. The man who does not stay, who is not what people believed — Finn has organized his entire self in opposition to that. Fic that uses this correctly has Finn feeling the specific shame of having believed the lie, and the specific resolve to be someone who does not lie about who he is, even when the truth is uncomfortable.
Rachel's dads (load-bearing in fic): LeRoy and Hiram Berry raised Rachel to believe she was a star before she'd ever performed. The love was unconditional; the expectation was enormous. She grew up knowing she was cherished but also knowing she owed them a dream come true. The ambition is partly love debt. She doesn't distinguish between "I want this for myself" and "I want this because they always believed I would do it." Fic that uses this correctly has Rachel sometimes quietly unable to tell which one is speaking.