I don't think you should even consider trying to salvage your marriage. You're married to a bullshitter with hidden debts & vices, who abuses you emotionally and financially.
Taking control of your future doesn't have to mean lurching precipitously from one crisis to another. Sometimes it means grounding yourself in reality, getting information, meticulous planning and playing a longer game. You're clearly tremendously intelligent; I think you'll find great satisfaction to this once you get stuck in.
I'm sorry some posters are being rudely incredulous about your predicament (not many, thank goodness!) FWIW, I was nothing like you but also a lot like you - independent, high earning (more than your CH for crap husband,) confident, outspoken, popular. BUT there were gaping holes in my understanding of life, which I wasn't even aware of. Consequence of faulty upbringing. Lacking such a resource as Mumsnet, i floundered when my marriages broke up and applied inappropriate values in my decision-making. I ended up with nothing, materially.
This isn't about me, and I am desperate to pass on some advice based on my experience.
Firstly, do an assertiveness course. I got a good one free from work, which opened my eyes, and followed up later with more therapy & coaching. A group course is better than a book (though there are good books,) because groups involve face-to-face practice. Most women's centres run them. Here's my favourite assertiveness primer to give you an idea of what it's about :)
Secondly, ring Women's Aid. Like many other posters here, I donate regularly to them so they can continue to fund helplines, which offer the chance to talk things through, in a pressure-free manner, with a wise & experienced person who genuinely understands your situation. After talking with them, ask specifically for a local outreach contact. This person will be available for you to talk to and, importantly, have access to the legal and financial advice you may need. Call them on a weekday - violent households tend to kick off over the weekend.
Thirdly, task yourself to Find Everything Out, about both your domestic finances and how things work in this world, currently, for newly-separated mothers. Keep using your thread as a guide what you need to learn, and where to look. Remember all the rules about verifying information and checking it currency. I promise you'll enjoy this!
Fourthly - keep posting! I can't overstate the value of Mumsnet to women developing their independence.
Fifth: Cover your tracks. Use private browsing, and still make sure you erase your cookies & history securely before you log off (CCleaner is a good, free app for this on a computer.) Change your passwords frequently - use an app like LastPass to generate new passwords and save them for you. Change your LastPass password often!
How're you feeling? A bit more empowered yet?