First of all, do your due diligence to make sure that the polygraph service is legitimate. Maybe even find your own and decide to go with them instead.
Just the fact that your wife found it gives me pause because you don't know how she framed the situation.
The other side of it - 10 questions is about 6 questions too many for any kind of standard consumer polygraph I have heard of.
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Outside of that, my advice is to use the polygraph as "pressure", to get as much of the the "truth" out of your wife before the actual polygraph day.
As I mentioned above I would ask her a boatload of specific questions, to which she can answer yes, no. She might also answer "I don't remember" but do not offer that option, as it generally equals that she does know and is scared to tell you the truth.
I would tell her that the polygraph will be used to verify her answer on the "Question and Answer Document" as a whole, as in, did you lie on any of the 100 questions I had you answer on the Q&A document?
Remember, liars try to "lie technically". She told you she had never been to a hotel with him, but she had been to his house. See? Technically true!
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The Q&A document could go like this (The question will get graphic, for those who may be scandalized)
Every question will be prefaced with: "During our courtship and marriage"
Have you had any affairs, inappropriate, or secret relationship with anyone?
Elaborate.
How many times?
Have you been naked in the presence of any other men?
Elaborate.
How many times?
Have you been partially clothed or in a state of undress in the presence of any other men?
Elaborate.
How many times?
Have you let any other men put their arm around you, as in your shoulder, waist etc.?
Elaborate.
How many times?
Have you let any other men touch your breasts either over or under your clothing?
Elaborate.
How many times?
Have you let any other men touch your behind either over or under your clothing?
Elaborate.
How many times?
Have you let any other men touch you between your legs either over or under your clothing?
Elaborate.
How many times?
Have you kissed any other men on the cheek or lips?
Have you kissed any other men where tongues touched or any saliva was exchanged?
Elaborate.
How many times?
Have you made contact or rubbed private areas with any men? (Define but not limit: private areas to face, backside, breasts, vagina, penis, etc.)
Elaborate.
How many times?
Have you engaged in any sexual act with any men? (Define but not limit: Any kind of penetration or activity in sexual zones and nature, and does not have to be naked.)
Elaborate.
How many times?
And on and on: List the places you have been with him in private and don't leave anything out no matter if it was innocent or not, Where did you go with him, did you badmouth or downtalk me, did you tell him you love him or any other form of that statement, etc.
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I know it is excruciating. However, when you are dealing with cheating liars they pretty much will not tell the truth unless they are cornered.
That is why it is imperative that you ask these questions as specifically as possible, and make her write down the answers!
Even then, she will lie. But it will build the pressure as you get to the polygraph.
I also second what others have said about checking her browser history etc. to see if she has researched how to attempt beat a polygraph.
[This message edited by faithfulman at 5:34 PM, March 24th (Wednesday)]