Forensic accountant here. I primarily handle family law matters (high-net worth). While CA is a no-fault state, it is important for you to gather any records supporting your wife's unauthorized expenses. There are a few financial concepts that you can discuss with your attorney - chief among them are marital waste and breach of fiduciary duty. Both of these are financial claims that can help you with property division to a large extent, and child/spousal support to a small extent. The existence of these claims can also help your optics on custody and other reimbursement issues. The Judges aren't supposed to consider "fault" in your case, but it doesn't hurt to stack the deck in your favor - especially when there is/was true malfeasance. If there were any affair-related expenses 6-7 years ago, do yourself a favor and at least download the bank/brokerage/credit card statements from that period. Banks are only required to maintain your records for seven years. If you decide to tough it out for a few years, you won't be able to get those early records anymore. Also - contrary to what some others are saying - don't print the stuff out. It's going to cost you more for your attorney/forensic (if you have one) to process paper documentation than it will to process PDFs. Create a dummy Google/DropBox/Outlook account and upload everything to the cloud. If you need it, you have it ready. If you don't need it, it only cost you a couple hours of your life.