Non-selfhelp book with theme about letting go of past mistakes (genuine mistakes and not due to circumstances)?

I want to read a book, with a storyline, with characters (aka not selfhelp) – whose theme discusses letting go of past mistakes, that cannot be blamed on circumstances?
I usually only find selfhelp recommendations or stories in which the faulters are given some form of "it's not entirely your fault" or "it's not your fault" excuse – usually backstory or stuff of the sort. I don't want that.

Any recommendations? Thank you!