KateIan
if he's hiding a mistress, then it's not unlikely that he's also hiding bank accounts/properties/stocks/bonds/etc

if you're entitled to half of everything, then you can only get half if you know about everything he has; from his secret shag-pad in the city and to the secret credit cards and checking accounts he has so that you don't see the bank statements detailing his dinners, hotel rooms, and present purchases for other women