1. A person shall not be convicted of adultery or of an attempt to commit adultery solely upon the testimony of the other party to the adulterous act or attempted act, unsupported by other evidence tending to establish that the defendant attempted to engage with the other party in sexual intercourse, and that the defendant or the other party had a living spouse at the time of the adulterous act or attempted act.

2. A person shall not be convicted of incest or of an attempt to commit incest solely upon the testimony of the other party unsupported by other evidence tending to establish that the defendant married the other party, or that the defendant was a relative of the other party of a kind specified in section 255.25.