No, you need to establish boundaries and consequences. My boundary was no sexual contact with other females. The consequence? D. I didn't have to take leaps of faith - I enforced my consequence. XWH had a choice - he could be with other women, but not with me as his wife.
Easier said than done, but essential, IMO, too.
There is one big site that favors using them to get to the truth, the complete truth…and usually the night before.
I mistrust any site that sees a poly as a way to get to 'the complete truth.'
Polys are limited to yes/no answers, and only a few at a time. Worse, many 'yes/no' questions can be framed by the poly subject in ways that invalidate the answers.
Worse still, if I believe the moon is made of green cheese, I'll pass a poly if I answer 'yes' to 'Is the moon made of green cheese?' IOW, as Bigger says, polys test only what the subject believes - their 'honesty'.
The 'truth' requires understanding nuances - and 'understand' does not mean 'accept'. Nuances can be the distinguishing factor between good candidate for R and poor candidate for R. If someone is a poor candidate for R, filing for D is probably more useful than doing a poly.
Finally, the web is filled with info on distinguishing truth from fiction and techniques for interrogating someone. If you use those techniques, you'll probably gather more data than any poly will get you. Human beings, IMO, are better lie detectors than any machine in existence is.
By all means, a poly is a great idea if a yes or a no will be the deciding factor between D & R. But a general reco to do a poly probably won't help.
Now, suggesting a poly may help make a decision if the WS keeps refusing to do one. In that case, though, the actual poly probably won't help. I'm OK if the WS says they'd be humiliated or feel like a criminal if they took the poly, because IMO those thoughts are not inappropriate. But a WS who keeps refusing is hiding something that shouldn't be hidden.
JMO.
[This message edited by SI Staff at 4:48 PM, Monday, September 16th]