I actually think that's a really important way to reframe the to-break-up-or-not-to-break-up questions.
So many OPs on these subs come at the question like a criminal trial. They're asking "Do I have beyond-a-reasonable-doubt evidence strong enough for it to be okay to break up?", but that shouldn't really be the question.
As you picked up, the key question is just "Do I feel safe with this person? Do I feel like my heart is in safe hands with them?"
Maybe the issue seems trivial (they destroyed a beloved childhood toy they knew OP was attached to, they did a cakesmash OP told them they hated), maybe there's uncertainty (no one will say what happened that drunken night and OP can't prove it, but everything points to they cheated and they're cavalier about OP's concerns), maybe everyone around them is telling them to stay together (because they dismiss OP's hurt, because they don't actually understand what the person did to OP, because OP and partner are 'meant to be together', or because they're terrible friends/family), maybe the partner really didn't mean any harm but can't be trusted not to do it again (addiction, mental health issues, chronically forgetful / reckless / thoughtless / stupid in a way that puts OP at risk).
At the end of the day it just comes down to: if OP no longer feels safe with their partner, no matter the degree of fault the partner is at and even if it's not their fault at all, they should feel okay to leave. Safety is a basic need. Higher ideals come after safety is secured.
And to be clear, you can absolutely fully and completely forgive someone but also know you don't feel safe with them anymore. Keeping your distance doesn't have to be anything to do with punishment. It can just be necessary if you don't feel safe with them.
^ We can't ignore the reality that the perceptions of family and friends can be important in some breakups, and then it might be necessary to formulate a stronger case. But for a lot of OPs it seems they feel like they need this kind of evidence just to give themselves permission to leave.
