If I break character I revamp my backstory for the character or evolve the character. As long as there is a way to justify the action its all good. People change. Mistakes are made. Some things cannot be forgiven. As long as your character doesn't commit suicide there is hope for the future.
I find it rather generous of me to create an indepth backstory for a character in a game that contains very little depth beyond what I'm imagining in my own head on the game's behalf.