Auch, I'm sorry to admit this, but your thread has just made me cry. I was raging before - still am - but have just read that you've called WA, which is so brave and so brilliant - and then you said you felt exhilarated at the thought of going - and that set me off.
You are absolutely doing the right thing. Please take all the advice WA offer you - and don't be scared to come on here when you need support - virtual or otherwise (lots of people will want to help practically if they can). I hope you're accessing MN via a passworded log-in ? .... please take care that he doesn't get wind of what you're planning just yet because he will try to persuade you otherwise as you're his cash cow.
I think once you're away from him it'll feel like a huge weight has been lifted from you. It's hard to envisage now because you've been used to this for so long and have been so worn down and worn out by it, but believe me, you will be amazed by how much better things suddenly become. I also strongly suspect that you'll see a big difference in your kids - I'm totally sure you're doing your very best for them now and obviously trying to protect them from what you're enduring, but at the same time, very sadly, they will probably have absorbed (even if not consciously) the fact that their mum is so stressed and worried all the time. You are absolutely doing the best thing for them by sorting this appalling situation out once and for all. Your standard of living - and theirs - is going to improve so much ..... okay, it may not be easy, but it will be miles better than now, and you'll have no-one to answer to but yourself, and no-one to manipulate you either.
I'm sorry to say he doesn't love you, and nor does he love the kids. If he did, there's no way he'd have behaved the way he has. I missed the earlier detail about your heart condition - how dare he fucking well put your health at risk by withholding money and/or snaffling a greater share than can possibly be fair ? And the rest of course. If he doesn't love you then what would the point in staying be anyway ? By leaving, you start on the rest of your life - and have the opportunity to meet someone decent at some point in the future (if that's what you eventually want) who'll treat you with real love and kindness.
As for him - he can go to hell. As others have suggested I too wondered exactly how much of the mortgage you're actually paying. Come to that do you actually see the other bills ? - or does he just demand "his half" ? Also agree that it's prudent now to copy everything you can possibly find - mortgage statements, bank statements, bills, wage slips and so on. Whether you can actually use this I don't know but it can't do any harm to gather as much written evidence as you can about your household set up. Just be careful you do this when he's guaranteed to be out for some time. Yes - solicitors cost, but many do still offer an introductory session at a reduced fixed rate so far as I know, and WA may also be able to recommend a solicitor experienced in this area who won't charge the earth.
You're being so brave. Keep posting and let "us" all try to help and support you through this - whether with reassurance, sympathy, advice/suggestions or whatever - however silly it seems, if it's worrying you, or if it's making you waver, don't feel ashamed of posting it - someone will always reply.