The judge decides what is admissible and the attorney representing you would take all steps to prevent its use. Highly doubt the judge would find it relevant. Tell your attorney about it.
NOT LEGAL ADVICE. FOR EDUCATION AND INFORMATION ONLY. Mr. Rafter is licensed to practice in the Commonwealth of Virginia and the US Federal Courts in Virginia. There is no implied or actual attorney-client relationship arising from this education exchange. You should speak with an attorney licensed in your state, to whom you have provided all the facts before you take steps that may impact your legal rights. Mr. Rafter is under no obligation to answer subsequent emails or phone calls related to this matter.
I respectfully disagree with Mr. Rafter. Idaho is a "one-party" state, where it is perfectly legal to record a phone conversation to which you are a party without any notification to the other party. The foundation for admissibility is laid by the party who recorded the conversation. The statement described in his post is perfect impeachment material, which can substantially impair the credibility of the witness. Remember, too, that this is a public forum available to your opponents.
Best wishes for an outcome you can accept, and please remember to designate a best answer.
This answer is offered as a public service for general information only and may not be relied upon as legal advice.