Ok, reading between the lines, I get the impression that he totally controls you, and even now you are scared to stand up to him. You say you had a great career and prospects which you put on hold...I had that too - my SHL is using that to go for spousal maintenance. Any good lawyer would do the same.
You say that if you go for what the CSA would class as the minimum (15% of £500k is a lot of money) then he would be unhappy, to say the least. So what? You invested time and effort and support into the home too. I guess, like a lot of us, you were the one juggling home/child/etc., to give him the opportunity to become the high earner he is.
You have to stop being worried about his reaction here. The law is on your side. With a good lawyer, you should be able to go for the same rate (my lawyer uses the CSA payments as a benchmark only) as CSA as a minimum. And you should probably get spousal maintenance.
I feel strongly that my kids should not have to lower their lifestyles because their father left. I supported my STBXH financially in the earlier days, gave up a good career to bring up our four kids...did 99% of the childcare, so that he could study, work his way up to being the high earner he is today. Are we entitled to our fair share? Absolutely. Am I entitled to spousal maintenance? Damn right I am!!
Get a lawyer who works for you. Recognise that the law is on your side. He may try to be unreasonable - but the law is there to ensure that you and yours are protected. He sounds a bully, you sound downtrodden by him. I can empathise with that.
However, at the end of the day, after a good lawyer has got you your fair share, you have to accept that what he does with the remainder is irrelevant: he can indeed spend all day being taxied around London in a Ferrari, lighting cigars with twenty quid notes....so what?
I work - I work hard; I contribute to the household expenses. I am happy to do this - I recognise that I need to, for myself, for my kids. For our lives and future. But I also realise that I gave so much to raising the kids, keeping the house, and enabling him to become the high earner he is today, to want my fair share too.