In my religion, we believe in the existence of
felix culpa, meaning "
happy/blessed fault".
This theological tenet is expressed in the most sacred prayer in the Catholic liturgy, the Easter vigil
Exsultet, where it actually describes the sin of Adam (in eating from the fruit of the tree of knowledge of good and evil which God had forbidden, after his partner Eve encouraged him to eat of it), in this way:
O happy fault,
O truly necessary sin of Adam,
which gained for us so great a Redeemer!
Sometimes a person's foibles, those little but very humanising quirks and faults that seep through the surface of our social roles, can be the most wonderful aspects of a person.
And more to the point, there's something reassuring about the idea that however bad we might screw things up, on account of our tendency as human beings to miss the mark, mess things up and fail to understand things rightly, that a higher power or fate can take that "mistake" and work it for good.
But not
all mistakes are
felix culpa. There's also the category of
mea maxima culpa, "
most grievous fault".
So, on the one hand, it can be the sign of an unhealthy mental disorder (OCD or scrupulosity) to feel that one can never let one's hair down
ever, never throw caution to the wind and have to live life always with a supercilious, constant policing of oneself.
It would not be healthy to treat every small foible of one's personality, for instance - normal little 'human' quirks, habits and failures - as if it's this dreadful transgression that makes one a complete hash of a person.
But on the other hand, by degrees and bad habits, conscience can be dulled and habituated to such an extent that through conditioned behaviour we become mired in far more seriously unhealthy or even harmful states of mind and ways of being.
For example, adultery occurs because someone is not being honest with their partner. That's not a species of
felix culpa but
mea maxima culpa.
Evidently, that relationship has problems that need brought to the forefront and earnestly addressed. Now, people do fail on such things but they need to take responsibility for it and make recompense, and admit that they have a problem / weakness. We all have weaknesses, that comes with the territory of being a fallible human with a proclivity towards sin.
But we need honesty about our foibles and sincere communication. Not sweeping them under the carpet and betraying someone's trust / hurting them. If it were consensual, open and fully transparent in the context of an open or poly relationship that's been mutually agreed to, on the other hand, then that would be morally sound.
So there are mistakes and then there are
mistakes.