Ultimately OP it sounds like your job is not feasible given your situation now. You need to start thinking like a single parent and not relying on him. He doesn't need to arrange his life around you now or vice versa so your job isn't appropriate for your circumstances. Many single parents have to make large career sacrifices, unfortunately.
I think you are conflating different issues, which the court will not consider to be related. You need proper legal advice regarding what share of assets should be reasonable to expect in your circumstances. A small investment in legal advice - even if you then attempt to reach an amicable agreement with him without court - is essential so that you don't agree to something disadvantageous to you.
But in terms of your life after that, you must accept that you must not be reliant on him anymore. Ideally, make your life manageable so that even if he never sees the children or pays a penny you can manage fine. And as an absolute minimum you need to ensure you can agree a reasonable fixed schedule of contact times and that you are not expecting any assistance from him during your time. If he does stick to being amicable and there is flexibility to occassionally both swap dates ad hoc sometimes to help each other or the children then great, but you absolutely cannot rely on this being the case. You must be realistic.
It is possible to find work that fits around being available for children, with regular hours/ flexibility. It is possible to maintain a nice home for children without a partner/ ex-partner contributing to it. It is possible for children still to participate in extra-curriculars but this requires careful planning around work hours/ reciprocal arrangements with other parents/ hiring a nanny or au pair etc. Yes, as a single parent that means your career is more limited and your costs are higher. Yes it's unfair, particularly given the tax system then charges us more tax on the same household income as a couple, on top of the higher inherent childcare costs, which is ridiculous. But many of us do it. And so can you.
I think you're still a little in shock and both he and you aren't really accepting the reality of the divorce if you are kidding yourselves that everything can stay similar to how it is now. It can't, sad as it is in terms of seeing the impact on your children. That said, if you make wise decisions now then in a few years' time you can be significantly better off than you are now, after unwisely prioritising his earnings over your own. Think carefully about what you can do for work now to a) significantly raise your earnings over the long term; and b) give you more flexibility.
Your children are already teens. In just a few years you will be able to access expanded career options again that involve travel/ night shifts. But for now it clearly isn't feasible. Be thankful you're not raising them for an entire 18 years alone!