Not sure that they will find out anything, glammanana, unfortunately. My DN has rarely been paid anything from her ex (they have 2 children); he earns quite a lot but manages to hide it as he and his father have a business. Says he lives with his parents when he lives with another woman in a large house, has holidays abroad etc etc. A really nasty piece of work so she has always been scared to rock the boat. The little girl always wanted to see him but the little boy refused (not from anything DN said about him), although they both see him now.
Kiora is right, some men don't deserve children.