does a spouse have to testify against their spouse
Both types of privilege are based on the policy of encouraging spousal harmony and preventing spouses from having to condemn, or be condemned by, their spouses: the spousal communications privilege or confidences privilege is a form of privileged communication that protects the contents of confidential communications between spouses during their marriage from testimonial disclosure, while spousal testimonial privilege (also called spousal incompetency and spousal immunity) protects the individual holding the privilege from being called to testify in proceedings relating to his/her spouse.
Spousal privilege