I'm asking what would make you justify leaving or staying.
Suppose you became deeply religious as a young adult and married someone of the same religion with a traditional promise to be loyal to them until death. Divorce was unthinkable to your spouse and you had repeatedly reassured them that you fully meant to keep your promise to never leave them, no matter what changes the future brought. You are now no longer religious and remaining married to this person makes you miserable in ways you are sure you can't fix without betraying who you currently are. Is it moral to leave your partner? Why and why not? (Don't worry, this is a hypothetical situation.)