How can I request financial documents in a divorce from the other party to determine whether that party has lied about expenses?

In civil matters (such as a divorce) there is something called the "discovery process" whereby one party can request the other party to disclose certain relevant documents.  In a divorce proceeding, where financial resources are constested, financial documents would most likely be subject to a discovery request.  In most states, the rules of practice (or the rules of court) set forth the procedures to follow with respect to making formal discovery requests.  In Connecticut, where I practice, a party has thirty days to respond to a discovery request unless that party files a motion for extension of time within the initial thirty days.  If a party fails to comply with a discovery request, they can be ordered to compel and/or subject to sanctions.  Therefore, you should have the ability to obtain these documents.  Nevertheless, the rules of practice can be tricky, and your failure to strictly adhere to them can subject you and your case to potential negative consequences; therefore, I suggest you consult with and/or retain an experienced divorce attorney rather than attempting to do this on your own.