I couldn't read and run - blimey! How on earth you're still standing through all of this, I don't know
You poor thing!
You most certainly didn't go too far. He is rude, dismissive, unfaithful, uncaring and tries to turn it back on you (which, without even reading any more of your posts, makes him abusive. As if you didn't know.) You were right: he is selfish and spineless. And worse 
I think you need to go to your GP - yes, about the PND but please make sure you tell them everything. Don't you see that anybody would be depressed and nervy in your situation, even if they were Superwoman on speed? Don't just blame your hormones; it's rational to feel depressed in your situation.
As to what you can do - If your "husband" won't do the decent thing, you'll have to divorce him. What on earth are you trying to appease him for? Continuing like this will destroy any self-worth you've got left, and that will damage your long-term health. You can't afford to do it, and your kids need a confident mum. Plus, it'll be a better example to them if you show them people shouldn't put up with being treated contemptuously.
It is going to be hard to extricate yourself, with so many kids needing so much attention. But it's going to be damn hard to carry on like this, so please take the first steps towards setting up a better life for your family sans loser H. Ask your GP for referrals and advice. Talk to your church - they may have untapped resources. Make an appointment for yourself with the CAB. Also, is there a supportive friend or relation who could come over for a week or so and let you put your feet up for a wee while?
I'd do it myself if I could! Please realise you deserve better than this; so your DC. It will be hard to change things. But worthwhile. Breaking the unwritten rules and sending you some (((((((hugs)))))))