I have a loving family, but because my Dad comitted suicide when I was 9 years old, I also know how mental health problems can bring some members of the family to think the worse. Throughout my battles with my mental health I have kept the vast majority of my problems from them because I don't want them to suffer even more, that's despite knowing they would help and support me.
So agreeing with you 29-Acacia-Rd,
It could have been the same for NB. And NOT-wanting family members to suffer, could be the reason why NB (perhaps) voluntarily planned her own disappearance. (Am hoping this is not suicide. or, accident. At least this other option leaves me with the belief that she is still alive, and safe somewhere.)
What if it really concerned her how much rage she had? (Am not victim-blaming here).
Maybe NB was worried she would make her partner suffer? by berating him too much? or, maybe by hitting him?
Maybe she was concerned for how little patience she had for her daughters lately?
Maybe NB didn't want to cause more upset to those around her?
Maybe NB didn't want the relationship between her and her partner to turn toxic? So, she needed to go away before things got worse?
NB could have been VERY concerned FOR her children and that they would be taken away from her, because of the previous visit by police, and wanted to pre-empt that process by removing herself so she "didn't do more harm"?
NB could have felt completely removing herself from the situation would be her only option ...in fact, she might have felt that desparate. And even though some of us believe a woman would never leave her children voluntarily, maybe, she found a Santuary Organization that was agreeable to her leaving in secret, and living with them awhile, so she could sort out her thoughts and get her mental health under control.
Going to her parents was not an option. Seeking outside support was the only viable option to stop the downward spiral.
If this is the case, I hope NB is getting the care she needs. I hope there is a Santuary Organization that is supporting her. I hope she can remain in hiding until she feels safe again. And without the glare of judgmentalism from the Media or Public Opinion.