I can't believe people behave like this. My dad is a higher earner and my mum, for the most part, a SAHM. Whilst in the heat of arguments (usually if my dad wanted to spend on something vast) my dad has been known to state "it's my money" in all fairness all their accounts and credit cards are joint and my mum probably knows more about the finances than my dad as she deals with it all.
Myself and DH have our own accounts (got together a little later in life than my parents) however we each put in a certain amount to a joint account which more than covers mortgage, bills and food. We then have our own accounts separate but this is mostly so we can buy presents etc online without the other seeing the details accidentally. Anything needing to be bought online, either of us will buy no matter who it's for. And we are not on even half of what your dh is when added together. Also we easily spend between £70 and over £100 a week on food and that's just two of us. £500 for a family is nothing!
I think you need to sit down and write it all out to go over with him. Something like "you get x amount, bills and shopping equals x amount, leaving this much. I think a fair division per month is 50/50 or 60/40 or something like that (make sure your percent amounts to enough but if you need to make him feel he gets more, then fair enough. Maybe even add in a percentage for savings) therefore I should be fairly transferred this amount per month"
If he argues, you tell him that he only makes that money because you have been there looking after his home and family and why should you live in poverty because you allowed his career to become more important than your life? Also (fact check this with a solicitor if you can) tell him if you were to leave, he would end up paying you a hell of a lot more in child support and spousal maintenance. And if you weren't there one day, the amount of a nanny and maid would be x amount.
So sorry to hear that he can be so tight. I'm sure there must be reasons you're still with him apart from the kids. However if there aren't, then maybe don't put yourself through the drama, get a secret check on him and prepare yourself to take half and live like a queen!
I also have to add, the fact that your parents pay for things for your kids when your husband earns that much, sickens me. Completely because of your husband (I understand you have to let them to survive) but I bet you appreciate them, you have an amazing set of parents and your husband should be ashamed in himself for that. I don't know how he can let that happen, but he certainly isn't acting like a man.
Sorry for the long post, OP I just feel so strongly for your situation as you deserve so much more!! 