I see a lot of focus on finding hidden bank accounts et cetera.

There are a few ways that someone with a secret life can spend money right out of the known accounts without being noticed. It's not large amounts of money but can add up over time.

1. Buying something at a store that has debit purchases / cash returns. Target no longer offers cash returns for debits but I know Home Depot does, and many others I'm sure.

2. Another way is by masking a Visa/MC/AMEX Gift card purchase in with a big purchase at a grocery store or big box store.

Maybe this will help some of you. And let me be the first to apologize if you're in a marriage where you have to scrutinize every receipt.