In any case, here is my concern.  If I have, and transmit to my wife, an STI, my marriage is likely over.  (Yes, I should have thought of that before I stupidly stepped out).  If you were in my shoes, what would you do relative to testing, if any?  I feel so so so stupid and am absolutely mortified about what I did.  What meaningful risks do I have here?

Thank you.

I'm sure you know you had a very safe exposure; the STI/HIV risk is nearly zero for vaginal sx with a properly used condom and no obvious condom failure. As for your symptoms, they do not fit with any STI:  with neither genital sores, discharge, or painful urination you can be confident you have no genital STI. In addition, the on and off nature of the symptoms is reassuring:  no infection of any kind is likely to cause symptoms that come and go.

I disagree it's "crazy" for anxiety to cause such symptoms; in fact, it is entirely normal and by far the most likely explanation for your symptoms. Anxiety is a powerful influence that can easily make someone overly aware of minor symptoms or even normal body sensation that would not be bothersome and perhaps not even notice except for worry. And such symptoms of the genital area are very common after sexual exposures that are worrisome and/or a regretted sexual decision. Physiologically, the symptoms result from increased bladder muscle tension -- in the same way that we name some headaches as "tension" headaches, which everyone commonly understands usually result from stress, anxiety, etc. (The physiologic mechanism is the same:  for headaches, it's increased tension in scalp and neck muscles.) For these reasons, your very words are themselves major clues to the cause:  you "very much regret the incident", "stupidly stepped out" and "absolutely mortified". And even the timing of your symptoms doesn't fit with any STI: Friday night to yesterday implies only 36-40 hours from exposure to onset -- too soon for any STI that might somehow be responsible. Finally, simply mentioning anxiety yourself also is significant:  whenever someone suspects their owns symptoms have an emotional or psychological origin, usually they are right! (In teaching medical students and resident physicians I could quote your question as a classical example of genitally focused anxiety.)

You would not put your wife at any risk by continuing unprotected sex with her. Should you be tested? From a medical/risk standpoint, I see no need. However, anxious persons often are relieved more by test results than by professional opinion, no matter how experts. (We don't take it personally on this forum!) If it would help, you could have valid urine testing for gonorrhea and chlamydia in a couple of days (4-5 days after the last plausible exposure); and for icing on the cake, maybe syphilis and HIV blood tests in a few weeks. This suggestions does not imply I believe you are infected:  I do not. I bring it up strictly for its possible reassurance value.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

Assuming you've never had HSV2, the risk for any single non-monogamous sexual exposure is well under one chance in a thousand. Condoms are ~90% effective in preventing it, making your risk no higher than one chance in 10,000 -- and probably closer to 1 in 100,000. In any case, low enough to disregard. And definitely to not seek testing, since the HSV blood tests are not reliable enough to use in this situation.