Today, almost all data is stored on computers. It is more than likely that your spouse maintains computer records of all his transactions, which may even include cash transactions that would not be elsewhere obtainable. Most business and professional persons maintain at least two computers. Normally one will be in their office, and the other in their home. Obtaining the information from the hard drives of these computers might supply a treasure trove of useful financial information that may form the predicate for your successful obtainment of maintenance, child support, and a division of marital property (equitable distribution).
When you have been allowed access to a home computer you would have the right to make copies of the information stored. Where such permission has been denied, your lawyer can make a motion to the court to impound and clone the hard drives. This should be one of the first actions taken in a contested divorce