Frayed cervix is a sort of generic description of what your doctor
most likely saw when they performed an examination of your cervix using a speculum at your last appointment. What this probably means is that they saw some evidence of irritation, bleeding
, or inflammation of the cervix. However, in order to know exactly what the significance of this might be, you will need to talk with your OB GYN doctor again, as they are the only ones who know exactly what they saw and the specifics of your case.
You are definitely right that one of the most common causes of "frayed cervix" is sexually transmitted infection. I assume that your doctor tested you for these infections when they performed the examination but, if not, that would be one good place to start. Similarly, it would be important to make sure the frayed cervix is not an early sign of developing cervical cancer but, again, this would be ruled out by a pap smear, which presumably your doctor also performed.
Finally, there is a normal finding that is common in many women, where the cell lining from the inside canal of the cervix spreads out onto the exterior surface of the cervix. This can lead to a "frayed" appearance, but it does not indicate any specific health problem.
Talk to your OB GYN doctor!