I had my girlfriend take a poly a couple monthes ago which she failed.  I really trusted her but I lost my trust when she got too drunk at a party and kissed someone else.  She said she would take a polygraph to prove it was an isolated mistake, which I could forgive her for.  I have been with her for over 2 years and was about to pop the question soon so it really has tore me apart.  I was so sure she would pass the thing I had flowers and everything, I wasn't using the test as finding truth or lie... I was trying to set us free, and stop any ideas in my mind.  For me $500 was well worth being able to sleep at night.
  Im tore apart because I just can't forget this whole polygraph thing, even if it isn't 98% like they quote.  I want her to take another one and said I would pay for it if she passed.  Taking the test in the first place might have been a mistake.  She says that the examiner used the term "sexual contact" and that she preferred that specific questions be asked that it was too broad.
  I consider myself pretty strong minded, but I just can't stop thinking about the result.  She didn't really make an effort to try and right herself, which is what bothered me the most.  If I failed a polygraph I would certainly do whatever I could to make things right.
  I am thinking about finding another examiner who will ask specific questions to try and clear my mind.  I am curious what the chances are of a second failed polygraph provided she actually is innocent?  If I had done research prior to the test I probably wouldn't have done it, but like many people on here I had no idea.  It's too late for me now, even with all the articles I have read I can't get the thoughts to go away.  Any insight or suggestions would be helpful.

Partsguy,

It sounds like you have major trust issues with your girlfriend.  If you don't trust her then no "test result" of any kind is going to change that.  And this in no way implies that you don't have valid reasons not to trust her - it sounds like you might.

If you truly want to make a go of this relationship you both need competent counseling.

Parts,

I doubt if a poly will fix the problem and/or trust issues between you and your girlfriend.  Like the folks above, I recommend pre-marriage counseling, etc.  Good luck.