Suddenly they have no privacy; they are unable to by secret presents, and there is no spending, however unwise, that the spouse will not know about. A much better system when starting out is for each partner to keep a private bank account while setting up a new joint account out of which household and family bills will be paid.
The only problem with this scenario, however, is that the stressed person will have to confide in his or her spouse about any outstanding debts. Many a spouse has a huge debt that has been undisclosed. While sorting this out is a matter for the bank manager, and the partner may not even have to know the size of the debt, he or she should know that there is one and that it is being dealt with by the financial experts.
If the debt is a family one, and not on either of the private accounts, of course the exact amount must he known to both parties and the steps taken to deal with it must be agreed. It may mean trading down on the house, re-mortgaging or having some other form of loan, but at least this is a mutual decision; once it has been made, the atmosphere may lighten. It may be that the family finances have received their day-today management from the wrong partner and that a handover of power is called for.