2006 New York Code - Spouse.

 
    §  4502.  Spouse.  (a) Incompetency where issue adultery. A husband or
  wife is not competent to testify against the other in an action  founded
  upon  adultery,  except to prove the marriage, disprove the adultery, or
  disprove a defense after evidence has been introduced tending  to  prove
  such defense.
    (b) Confidential communication privileged. A husband or wife shall not
  be  required,  or,  without  consent of the other if living, allowed, to
  disclose a confidential communication made by one to  the  other  during
  marriage.