One reason many arriving here feel stuck in "staying" is that it is so hard to change "what is", that it might turn out to be unproductive or even disastrous. Yet, with forethought, strategies and planning it doesn't have to be that way. So the recommendation for you to quietly seek confidential and private legal advice is wise.
It is often mentioned that when repairing damaged relationships, sharing is important to restore trust. But when a relationship has clearly failed, then it is time to be very cautious about what you share - your options and strategies - or else you risk being sabotaged.
William Eddy's inexpensive but excellent handbook Splitting: Protecting Yourself While Divorcing Someone with Borderline or Narcissistic Personality Disorder has helped many here protect themselves, not just from the discord and dysfunction but also from the many possible legal pitfalls when seeking a divorce from someone so uncooperative and obstructive.
As for that feeling of having no support... how supportive are your children? While their childhoods may not have been normal ones, your influence over the years hopefully have had positive impacts. For all you may know, they might wish for you to find a better outcome than what exists now. And hopefully at least some or all of them could be your advocates.
Years ago, after my initial separation, I still didn't know what to do next. Once I accepted my ex still disparaged me and didn't want to reconcile, I filed for divorce first. I never regretted filing first. It allowed me to proactively structure at least some of my post-marriage life. Although every resource stated it legally didn't matter, I did feel better that I was the Plaintiff and not the Respondent. For me that was a Boundary shaping action. Though she posed as a victim - a very aggressive victim - I knew the reality and so did the System, eventually.





