For me the main thing isn't knowing for any kind of gain, but if you've signed things, then from now on you want to know what you're signing, you want a copy if possible. For nothing more than you understand what you're putting your name to.
For all you know you could have signed in the event of us splitting I don't want anything. I know that's an extreme example, but if you look at high profile divorces, the women are doing quite well, getting allowances and so forth.
It's nice that you are so trusting, I'd hope with all my heart DH had your best intentions at heart. For me, you have lots of assets, lots of money, things are secured for the futures of your DC. Does DH need to keep pushing making so much, it sounds like you're very wealthy as a family, at what point do you say to DH, what are your retirement plans, are you planning on stopping work completely.
Also I understand wanting to be really wealthy, so when you hit one target it's about the next, but is it beneficial, would you benefit more if over a certain period things were wound down? So he can spend more time with DC before say, the youngest, goes into boarding? Or from his childhood does he have a different perspective on parenting to you? You're more hands on, he's in the background, but does like the sailing etc with them.
I think the biggest lesson, having hobbled up the path of parenting, is it goes so quick, if your DH wants to establish a mutual hobby, that's better sooner than later.
That could be a selling point for you staying in London, so they have boys time together. Does that sound like something that would benefit you both mutually? With you popping down the odd weekend.
Possibly speak to DC and get them to write a bucket list of say 20 things they want to do.
You've have the resources to allow them to do lots, build those memories, try and knit in DH as much as possible.