Hi there,
I was where you are now, this time last year. I was desperately unhappy, found him menacing, was too afraid to do anything about it, fearful for my kids but also worried that they'd hate me for splitting up.... and its taken me another year to do something about it.
A couple of weeks ago I phrased something incorrectly and got a roasting over what I should have said....it was a turning point. I too strongly suspect NPD and I just thought - you know what, nothing will ever change, because he will never accept his behaviour is unreasonable.
So I went to work, sent him an email telling him I wanted a divorce (cowardly but the safest route I believe), and contacted a lawyer.
The wheels are turning slowly and after an initial outburst of how selfish I'm being, that I'll destroy the kids etc, its all gone very quiet and everything is now very civilised. I know that this is the calm before the storm so just taking one day at a time (with the odd wobble!).
I have agonised all year about how to do it, how I'd manage, financially survive etc etc but on that day it didn't matter. I just knew I had to do something about it. I have no idea how it will pan out, who will end up living where... but I do know that my kids will be safe, I will be happy and that we won't be homeless. And that for me, NOW is enough.
What I'm trying to say is that you will know the right day for you, when it comes. It may be over something trivial or something major - but you will know.
I started off with the CAB who immediately referred me to an EA counsellor. Maybe that would be a good starting point for you?
take care and be safe, you are (sadly) not alone.
V