Is it possible to have herpes without knowing even if you go to your doctor visits regularly and never told you have herpes until years later?

Yes: Herpes is not something that is tested for on a routine basis at gynecological examinations. You could have had a mild breakout of Herpes at some time that you thought was something else or even a subclinical case which caused no symptoms. In order to protect yourself from sexually transmitted diseases unprotected sex is a no no, and even then not 100% effective.

Yes: The time between the initial infection and first outbreak can be quite long. The virus lives in the nerve cells and outbreaks can be triggered by illness, irritation of skin, fevers, infections, exhaustion, poor nutrition, etc.. Also antibody (blood test) testing is NOT an accurate way to determine how long someone has had herpes. That test can be very misleading.

Yes: You could contract Herpes and not know it for a long time, symptoms show up when your immunity goes down for any reason, even stress.

Possible: Doctors not unable to check you for every possible diseases especially if you don't have complaints. Herpes can be dormant and comes out only when you have a stress or illness. Also if you don't have symptoms you swab could be false negative for herpes.