Spousal Privilege: in court cases (the marital confidences privilege and the spousal testimonial privilege).
The marital confidences privilege is a form of privileged communication protecting the contents of confidential communications between husband and wife. This privilege applies in civil and criminal cases. When applied, a court may not compel one spouse to testify against the other concerning confidential communications made during marriage.
The privilege generally applies only where both of the following fact situations are present: (1) a third party was not present during the communication (the presence of a third party would destroy the confidential nature of the communication), and (2) both parties intended that the communication be confidential.
The privilege is usually restricted to confidential communications made during marriage and does not include communications made before the marriage or after divorce. The privilege does, however, generally survive the divorce; that is, a person can be prevented from testifying about confidential communications with an ex-spouse made during the marriage.
Either spouse can invoke this privilege, either refusing to testify against their spouse or preventing their spouse from testifying. Finally, courts may require that the communication relate specifically to the marriage.
The spousal testimonial privilege (a.k.a. "spousal immunity") can be used to prevent any party in a criminal case from calling the defendant's spouse to testify against the defendant about any topic. Under the U.S. Federal Rules of Evidence, this privilege attaches to the witness spouse; that is, the defendant's spouse can refuse to testify against the defendant, but the defendant may not prevent his spouse from testifying against him or her.
This privilege does not survive the marriage; that is, after divorce, there is no right to refuse to testify against a defendant ex-spouse. This privilege may be restricted to testimony about events that occurred after the marriage, although in some jurisdictions it may apply to testimony about events occurring prior to the marriage (giving rise to a questionable incentive for an individual to marry a potential witness in order to prevent the potential witness from testifying against the individual). A marriage having such a motivation was depicted by Agatha Christie in a detective novel.
In the case of LGBT people we are treated as near strangers by the courts. This means that we can be compelled to testify against our partners or even legal spouses because the government does not recognize our relationships as valid.