There is a process called discovery, wherein either party may request their spouse to answer a series of questions or turn over documents.  Further, once the process has started, it must be supplemented occasionally until there is a trial or settlement.  This process is time consuming and expensive.  Most notably, without a doubt, it is one of the aspects an attorney hears the most complaints about, as it is usually one of the most frustrating aspects for the client.  However, without discovery there is no context to determine if the agreement is fair.  And, if you do discovery and your spouse does not disclose an asset, but you later find out about it, you have a right to return to court and ask for your interest in it.  If there is no discovery, you cannot ask for it.