Bless your heart...it seems like you make one mistake and it turns into a snowball.
I read what your wife said, and was struck..I've heard this one before..when my husband threatened to leave me; not once but several times..and the funny thing was that HE started the argument, not me..just like he'd started the WHOLE shebang...not me.
Now, the advice about not putting your children in the middle of it is right on the money. We have one son who was 15 at the time my husband was going through, and I did everything I could to keep him out of it. He asked a great many questions, you can't hide much from a teen or young adult. I gave him age-related answers that were closer to adult answers, based on his age. I do remember encouraging him to connect with his dad, regardless of what his dad did..and I took the high road, refusing to make him choose sides..that would have wrong of me, and not my decision to make.
But I digress.
Anything you say to your wife is going to be construed as control, and she will run farther away from you. It's confusing at best, trying to keep up with what's going on. Sorting the garbage is an exhausting task, as the "spewing" contains truth within the lies that are told as they attempt to "rewrite" history, coming up with some of the wildest stories you ever heard in your life.
Best to detach from her drama, leave things alone, if you can, focus on you and your life; taking your journey toward a better YOU...leaving her to twist in the wind for now.
The most innocent and simplest things can set off a tirade that can last for hours, if not days...and you NEVER know what will happen next.
Hang in there, hopefully this won't last forever, and things will get better in time.
Focus on YOU; don't worry about her; best advice I can give to you.
Remember, as each person is different, every MLC/Transition is different..what works for one may not work for another. Most of the time it is trial and error for ALL involved.