Ha. Well, big shock awaiting Mr. BullyBoy if you choose to implement it.
NEWSFLASH - 'his' money is not 'his' money. You are married. You are a family. He has the privilege of getting to live within a family, have children AND earn money because other team members take on other aspects of the work, like taking care of the kids during work hours. I.e. YOU.
I would not leave, no. Instead I would call the CAB and Womens Aid and a solicitor and get some advice, pronto. Because he needs to be put firmly in his place with a few cold hard facts about what the legal positon is here, and fast. Because he is talking utter shite.
Do you own your home? Then if you file for divorce, you can get the house forcibly sold and the majority of the proceeds would come to YOU as you would in all likelihood have care of the children, and their housing needs take priority. While this was happening, and you were living apart, he could be forced to continue to pay the mortgage. You would get a part of his income come to you as maintenance.
Do you rent? Then take advice on how to get him to leave and take over the tenancy. Then file a claim with the CSA for him to start paying maintenance. Your tax credits would increase. And he would have the doubtful pleasure of starting over again in a nice cheery sole tenancy somewhere else, where, let's guess, he no longer has you washing his socks, making his meals, and when the children come to stay with him he has to look after them by himself, sole responsibility.
Arm yourself with the info, sit him down, and tell him that his money isn't his, it's family money. You have as much right to decide how it is spent as he does. If he disagrees, here are the facts and figures - he is welcome to leave and formalise everything through divorcing, splitting the assets, and starting to pay maintenance. Because THAT is the only legal way for him to be able to claim that any part of 'his' money is his own... when you have split.
So he can either join the family properly and stop arsing around with all this 'I control the cash' nonsense, or he can LEAVE the family and fend for himself. With all his lovely (less maintenance) cash.
Don't take this crap any longer.