I'll add to what AN just said. Cancel all joint credit cards. Open up new credit card. Open up new bank accounts in your name in a different bank. The post office box is a good idea (but hide the key better).
And $2,500 may sound like a lot of money (okay, it is), but that's the going rate on a halfway decent divorce attorney. (My wife normally charges double that, and she's charged as much as $10 grand on a case that looked to be a p!ssing match.)
