There are discovery procedures available to your lawyer that should enable him or her to obtain the payor's income records. You should carefully review these records with your lawyer so that you can point out which portions appear to be inaccurate. Do not simply rely on the payor's statements about his or her level of income. Even though you may have lived with the payor and think you know all about his or her income, it is still a good idea to demand all income-related documents. There may be some things that the payor may have held back or kept secret.
Tax returns are very important documents to review.
They should contain all income-related information. But even tax returns don't always tell the whole story. If the payor is self-employed, you should request bank account records, which may paint a more accurate income picture than tax returns do. One advantage of formally requesting income information through the court is that a payor who lies about his or her income can be subject to perjury charges. Make sure the payor knows this.