Mich. Comp. Laws § 750.461: Competency of person to testify for or against accused notwithstanding person's marriage to accused.

Sec. 461.

An individual referred to in sections 455 to 459 may be a competent witness in a prosecution under this chapter to testify for or against the accused as to any transaction or as to any conversation with the accused or by the accused with another person in the individual's presence regardless of whether the individual married the accused before or after the violation or whether the individual is called as a witness during the existence of the marriage or after its dissolution.