N.Y. Civil Practice Law & Rules § 4502: 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.