Not a good situation but some facts we haven't had:
What is your relationship like generally, do you laugh? Is he good with the children?
What is your relationship like with your parents/his parents - what do your parents in particular think?
Would you consider going back to work and getting your own independence and autonomy there. I hated spending "shared family" money and was always much too careful over that to the point where DH used to sometimes leave me money and tell me to specifically replace clothes/hairdressers, etc.
How much housekeeping does your DH give to you and does he provide for your every need, the DC's every need, can you all have pretty much what you want.
Do you have to scrimp at the supermarket, do you or the children ever have to go without, do you have to watch the heating, etc.
I'm not saying what your husband is doing about the money is right; but I'm not convinced he's doing it for the wrong reasons. My DH wasn't secretive if I asked, probably a generation ago now, but neither did he readily disclose that sort of information when the children were tiny. He grew up in relative poverty and I think he was always scared that if he didn't preserve money then his children might too.
I'm just not getting a feel from the thread about your circumstances overall and whether in other ways he's a good husband and father.