OP your not providing any extra context or answering questions!
Why does any extra money not go to his children?
How long have you been asking? And why do you feel you need to know so badly you would divorce? Maybe he doesn't get why you need to know all of a sudden and worried your attempting to divorce!!!
FYI, my husband and I don't have shared accounts, I agree that you should know what the pot is, though not simply entitled the lot.
My will and life insurance ensures my children own my estate, he will be paid a 'salary' from if worst comes to worst. But in no way will he or future partner(and her possible children) benefit from my hard work!
That sounds awful, but several friends of mine, who have lost a parent, saw their parent move on, usually with partner with children of their own). They then sold the family home and insurance money from deceased parent was then the new family's money pot and used up paying for other people's children, not in them or their future.