If a $10, over the counter, sold at the pharmacy testing probe, that only needed a little urine or saliva to be placed on the diagnostic tip of it( similar to a pregnancy test), to determine, 100% accurately the number of partners a woman has slept with, what effects would this have on society?

How would this change the relationships women and men have? How would this impact female promiscuity? What effect would this have on marriage rates?

For example, in theory, a male could take a saliva sample from a female's fork at dinner time or her straw she drank out of, and perform the test secretly. How might this affect the honesty between couples?

Please note, I am not looking for people disputing it would never be possible to create, or it would never be over the counter or legal. I am not interested in hearing that it's sexist. I am looking to discuss what kind of implications this would have on society if it could in fact exist.

EDIT: This test could work for both genders, I only posed the single gender case for a specific poster for further discussion.