That said, until it happened to me I really couldn't understand how anything could get so bad that you wouldn't be able to have your parent in your life anymore. I certainly never thought it would be something I'd have to deal with. Not that I would have thought that people who did go NC were terrible people, but I would have just thought that there was something very different about their lives and their relationships with their parents then my own.
But the destruction that has been caused in my family by my mum and her partner and their choices (which unfortunately also involve her knowing he has engaged in sexually abusive behaviour with children since his original offences, that he was arrested and convicted of, but working very actively to normalise it and pretend its fine behaviour between adults and children), it's just been something that is no way to ever come back from. It's destroyed my trust in the people I trusted the most.
I tried very hard for a long time to heal that relationship and try to find a way that we could still have a relationship but not involving my dc and not involving her partner. But literally every conversation with her turns around to what a horrible evil person I am for not understanding that what he did wasn't really that bad, how horrible his daughters are (who he sexually abused) and how much trouble they have caused them (they have been NC since they were late teens, we're all now 30s and 40s), what a cruel person I am for not letting them have contact with my dc, etc, etc.
The cost on my mental health and my actual physical health has been horrific (as a result of the stress, I became physically ill and now in the process of likely being diagnosed with an autoimmune disease). I couldn't keep doing that to myself or confusing my children about what if any relationship they would have with their grandmother who dipped in and out of their life being shouty and mean every couple of months. Literally I would feel well, be happy, family life would be great, and she'd pop up every month or two sending me abusive messages about what an awful person I am and how terrible I have been for not overlooking all of this. There comes a point when you recognise that your own wellbeing and that of your family is more important than maintaining any sort of relationship with a biological parent.
I think until you've reached that point where you literally can't go on without freeing yourself from someone doing this to you over and over again, it's incredibly difficult to imagine how horrific it is and also what a change it can make when you don't have to live in that cycle anymore, with your heart dropping to your stomach every time someone knocks on the door unannounced or a message comes through on your phone.