1. The normal course would be to hire a solicitor and get proceedings drafted for slander. Witnesses are key as the oral remarks of what was said has to be proved if you are taking an action in slander. Do you have any key concerns?
2. What was said and who was it said to?
Wife left me after 36 years married. Have heard from mutual friend that wife has heard form "several sources" that I have been unfaithful which is totally untrue. What action can I take please. I do not know excatly what was sid, nor byu whom.
Am prepared to swear in court
3. Here you need to chat to your wife before you can take legal action as otherwise you have no evidence upon which to take legal action. Find out who said this to her and then you can know who to sue.
4. Essentially, you need to find out from your wife who has been saying these things to her. Then you can confront these people and sue them.