One perspective about being in a relationship with a narcissist and having children is….
Some choose to stay to protect their children, because if you split up – the toxic person will get to see the children and the decent parent will not be there to know what’s happening. And the decent parent cannot help the children, if they don’t know what they are being subjected to.
So staying together enables the decent parent to be aware of everything going on.
Plus, there are so many people who suffer through terrible divorces and go through hell trying to co-parent with a narcissist.
And the children suffer the most.
In some (not all) situations – it is an act of greater love for the children, to remain in the relationship.