[header] How to prepare as a witness in an adultery case [title] Talk to an attorney. [step] If you are one of the parties in the case, you'll be working with your own attorney regarding your testimony as a witness. If you are a third-party witness, you'll meet with the attorney who intends to call you to discuss your role as a potential witness. 
[substeps] If you are a party to the divorce, you generally will be expected to testify-particularly if the divorce is fault-based, as in an adultery case. However, keep in mind whether you testify is ultimately your decision.