is it lega for my wife to cash a $10.000 check and keep every penny for her self

The answer is: it depends.  Nevada law has long applied a presumption that all property acquired during marriage is community property [and thus shared and owned equally between spouses].  . However, property acquired during a marriage by gift, bequest, or devise is presumptively the recipient's separate property. Therefore the source of the monies will determine whether you have any rights in the monies cashed by your wife.