I think your post raises interesting questions, especially feminist ones. Many women come to realise that there is an unequal burden when it comes to raising a family that does not end with the end of pregnancy or indeed maternity leave.
You are in a relatively privileged position of having a substantial income that you are able to sustain even after having your children. I can see that you are looking to a potential future where all of the burden of raising your children would fall to you and join many women before you, who have faced this reality.
The reality of marriage and divorce in the UK, is that assets of the marriage are split in some way approximating 50/50 on divorce and thereafter, the non resident parent makes a relatively small contribution to the resident parent and they are free to pursue their career and life more freely than the resident parent.
By entering into a prenup, you and your partner have sought to separate your partner's 'considerable asset base' from the marriage, preventing any possibility that you might share in that wealth on divorce. Your current position is that you no longer thing that is fair, because you observe that you already take on an unequal burden of parenting responsibility and that you should be compensated for that sacrifice and effort above and beyond what you might get in a divorce settlement.
There was a reddit shared a few weeks ago where a woman requested that her partner pay her a multiple of his salary to compensate her for carrying their child. The reality is that the majority of women have greater adjustments to make to their lives as a result of choosing to have children than men do. Many of us do not truly understand the impact of that, until we have children and find that despite believing were are emancipated and in equal partnerships, this is not truly the case. I also believe that many men find themselves in a similar situation, from a different perspective, not truly understanding the changes that would come with becoming a father.
I haven't really heard what your argument for having the prenup set aside?
What is different now than at the beginning of your marriage, which I presume you entered into with the expectation of having children?
In what way do you see the arguments on this thread as being misogynistic? Is it not misogynistic to presume that you will take on the majority of the childcare and responsibility for housing the children... what if they were to spend 80% of their time with their father, taking advantage of his significant assets and 20% of their time with you in your adequate assets and significant income? They would still get the lifestyle they are used to with their father and you would have the lifestyle that your income affords you.
Are you right to demand a higher share of his pre marriage assets despite being in a position to have been able to maintain your income and being entitled to a 50% share of the assets of the marriage? Is that the question you really should be asking - should it instead be - how do we make our marriage more equal and how can I reassure myself and my children that my husband will give my children the life they deserve and support me as an equal partner?