Husband-wife privilege – Within the sphere of the Family Law in most jurisdictions (somewhere known as “Marital privilege”, the term is used to refer to a special legal right given to married persons to keep communications between them secret and even inaccessible to a court of law. While this privilege may have been varied in some states, it has always been held to be lifted where one spouse commits a crime on the other. Similar to the client-solicitor privilege.

See also http://www.wisegeek.com/what-is-marital-privilege.htm