Itscurtainsforyou and timeisnotaline are correct about a clean break not affecting statutory CMS child maintenance.
Here is some info about spousal maintenance (also called periodic payments) I learnt through life experience that might help you, OP, and/or other PPs. (The info is from the perspective of the law in England)
It's just meant as background, to give you a heads up. Not to replace legal advice (I'm not a solicitor).
Given what your DCs will need from you in the future and the backseat that your earning capacity has taken (compared to the career development its sounds like your STBXH has been able to maintain during the marriage), you may well have a good case for spousal maintenance on top of a bigger split of the assets. Even if he deliberately loses his job, the courts might attribute earning capacity to him when assessing a claim for spousal maintenance (whereas the CMS don't take account of whether he deliberately chucked in his job). (But they also take account if his job is precarious).
In England, the statutory criteria for spousal maintenance are set out in section 25 of the Matrimonial Causes Act 1973.
www.legislation.gov.uk/ukpga/1973/18/section/25
There is also some important case law (judge made law), which explains how judges are supposed to interpret the word 'need'. Basically - there is no general formula for the court’s assessment of ‘needs’ – it is necessarily an elastic case-specific concept – but the courts have identified some factors to assist case-specific determinations. (I can give more info if it would be helpful.) 'Need' does not mean what you 'need' to avoid falling below the poverty line. 'Needs' reflect to some degree, and to the extent financially possible, the economic standard of life during the marriage. Hence the exW of a rich, celeb couple might get large spousal maintenance payments; the exW of a poor couple will not. (It's not a very sensible use of the term 'needs'; it's a legal use of the word).
Spousal maintenance can seem like a good thing - like on-going money. However keep in mind that a spousal maintenance order can be a nuisance to enforce if he plays silly buggars and doesn't pay. And in time, if his or your circumstances change, he can apply to 'vary' a spousal maintenance order. So spousal maintenance is not as 'real' and as reliable as getting a really good split of existing assets. Not all solicitors mention this; I think they assume we know this or it's obvious. But it wasn't obvious to me. Sometimes you have negotiate a financial settlement that includes both a split of assets somewhat in your favour plus spousal maintenance because there aren't enough assets to support both parties housing needs and pay for the future needs of the person who will continue to be financially limited by the marriage. Time is needed for the other person to earn income - hence spousal maintenance payments over time.
If you are willing to move to a smaller, less expensive house and you are the primary carer, then he won't be able to argue he 'needs' a bigger house than you. (He will be able to say he 'needs' a house with similar number of bedrooms to you so that your kids will be comfortable when they visit him).
Bottom line - a spousal maintenance order is helpful but not 'definite'. Get as good a split of the hard assets as possible. Sometimes being willing to agree to forgo spousal maintenance is a good negotiating tool.
On a non-financial note, spousal maintenance is emotionally draining. It leaves you tied to him, and open to his whingeing about you sponging off him and him financing your lifestyle. You have to remind him to pay (even if the order says he is supposed to set up a standing order chances are he won't, or he will and then he'll cancel it etc.) And each year you have to work out the increase with reference to RPI/CPI. And then get him to vary his standing order. So in short - you have to keep thinking about being linked to him.
PS if you do need some spousal maintenance - don't listen to his whingeing. It is not him paying for you after you are divorced- he is paying because it wasn't possible for the parties to achieve a fair split at the time of divorce. He pays over time so that the marriage split is fair in time taking into account the children's welfare and how having children in the marriage affected you financially in the past and into the future.
If his earnings exceed the statutory CMS limit, you can also apply for court-ordered child maintenance. Again though, you will have the complexity of enforcing such an order. So getting the assets up front and then managing them through investment could be better if family finances allow.
NB there is what one might call a 'hard clean break' and a 'soft clean break'. With a hard clean break - you have no right to bring a future application to reapply for periodic spousal maintenance . With a soft clean break, you basically settle up but there is also a clause which allows you to bring a fresh application later if something serious happens. Judges don't like exWs to see this or spousal maintenance as a meal ticket for life, but some people like to retain this option just in case they or the kids had a bad accident for example. Your solicitor will know about this. (Make sure you don't leave it open for him to claim against you in the future. You will have enough to worry about as primary carer for 4 DCs. It's unlikely, but not unheard of, and easy for your solicitor to insert a clause in the order to prevent this. )
Another long post - sorry folks. Hope it is useful to some people!