Wis. Stat. § 905.05
A wife's testimony as to statements made by her husband was admissible when the statements were made in the presence of two witnesses. Abraham v. State, 47 Wis. 2d 44, 176 N.W.2d 349 (1970). Spouses can be compelled to testify as to whether the other was working or collecting unemployment insurance, since such facts are known to third persons. Kain v. State, 48 Wis. 2d 212, 179 N.W.2d 777 (1970). A wife's observation, without her husband's knowledge, of her husband's criminal act committed on a public street was neither a "communication" nor "private" within meaning of sub. (1). State v. Sabin, 79 Wis. 2d 302, 255 N.W.2d 320 (1977). "Child" under sub. (3) (b) includes a foster child. State v. Michels, 141 Wis. 2d 81, 414 N.W.2d 311 (Ct. App. 1987). The privilege under sub. (1) belongs to the person against whom testimony is being offered. While an accused may invoke the privilege to prevent his or her spouse from testifying against him or her, the witness spouse may not invoke it to prevent his or her own testimony. Umhoefer v. Police and Fire Commission of the City of Mequon, 2002 WI App 217, 257 Wis. 2d. 539, 652 N.W.2d 412, 01-3468. Under sub. (3) (b), it is irrelevant whether the acts of the defendant that constitute a crime against a third party are the same acts that constitute a crime against the spouse or different acts. State v. Richard G.B., 2003 WI App 13, 259 Wis. 2d 730, 656 N.W.2d 469, 02-1302. When all outgoing telephone calls made by inmates of a jail were recorded and that policy was disclosed to all inmates, the defendant knowingly exposed the content of the call to a third party. That constituted a waiver of any marital privilege. State v. Eison, 2011 WI App 52, 332 Wis. 2d 331, 797 N.W.2d 890, 10-0909. The fact that the defendant was untruthful in his statements to his wife was not an exception to the marital privilege. State v. Eison, 2011 WI App 52, 332 Wis. 2d 331, 797 N.W.2d 890, 10-0909.