N.Y. C.P.L.R. 4502

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