What I see as an outsider is that you get lots of great advice from several people here and yet you spin paragraphs to rationalize how their advice doesn't exactly apply to you.
You seem to pick and glen what advice you like but ignore the parts you don't want to deal with... I've seen that a lot lately but I will let the others weigh in on that observation as well. Perhaps I'm not seeing things correctly.
As for repairing trust in a relationship post A - yes it requires 100% transparency BUT... and here is the part you are not getting .. it requires the WW to open up everything to you to show she is being honest and in this 100% with you to where she accepts your scrutinizing her every move. If she is closed off and not willing... you have every right to not believe her and walk away.
Spying on her with listening bug devices places you no better than she for having an A. You don't have her agreement to take part in this... this is not her being 100% transparent. This you treating her as a prisoner with no rights.
If your WW is not on board with being 100% transparent then you are not a place where you can recon the M. And, trust me if she found out what you were doing she may very well up and leave for good. She will run to Rodney saying to him - you have no idea what he has stooped to now...
Your WW may very well be confused at this point and filled with regret but she is still on precarious scale that could easily shift back to Rodney and you are adding fuel to the fire.
What happened to being the spouse only a fool would leave?
A spouse that only a fool would leave would place definite boundaries on acceptable behavior. Expect the WW to be 100% transparent without having to go to the level to spy in such a way. Otherwise you are just fooling yourself that she is there to stay.