To answer your question literally, the MOST likely scenario probalby is that your wife got both a garden-variety urinary tract infection and candida vulvovaginitis (yeast infection, thrush). And you might have nothing, perhaps just anxiety magnifying normal body sensations. Both yeast and UTI are common in women and not sexually acquired, and symptoms like yours are common in men who are concerned about having an STD.
That's the good news. Here is what you are hoping not to hear: you and your wife both need to be evaluated for STDs. If your wife's doctor wasn't aware she was at risk for STD, s/he might not have tested her for gonorrhea, chlamydia, trichomonas, herpes etc--all of which are commonly confused with yeast and UTI. And if not specifically tested, providers often do not suspect them. Further, depending on what antibiotic she was given, it might or might not have treated an undiagnosed STD.
Which of these scenarios is most likely? The first. But the second is a real risk, and not addressing it directly may result in significant health risks in your wife. Therefore, you cannot duck your responsibility. If you like, you can get tested first; but even if your test results are negative, your wife will need to be tested. (The least likely scenario, by the way, is your wife's yeast infection causing your symptoms. It is conceivable you are reacting to her vaginal medications, but in that case your symptoms would go away within a couple days of her stoping the pessaries and antifungal cream.)
Good luck-- HHH, MD
Another approach would be for you to inform your non-marital sex partner about the situation and suggest that she be examined and tested. If she is free of STDs, it makes the non-STD scenario more likely; or if positive, you will have specific information to pass on to your and your wife's providers. But since STDs can clear up spontaneously, this approach won't necessarily mean your wife doesn't need to be examined.
It probably doesn't need to be said, but it would be safest if you and your wife stopped having sex until this is sorted out; or use condoms.
Would gonorrhea, chlamydia, trichomonas have cleared up
from Mid December until now without treatment??? Wouldn't the
approach of testing his non-martial partner be conclusive?
If she's clear and he's clear, does he need to go further???? Also couldn't he be tested for yeast infection, etc to specificly indentify the source of the problem just to confirm the cause wasn't an STD?
This is of course assumes he has had no other partners.
of course I'm not suggesting any action that would put his
wife at risk. Just hate to see him risk his marriage if there's another way.
But if his non martial partner has unprotected sex with other partners outside of her long term relationship besides him as he suggests , he needs to terminate it. He can't in the future continue to put his wife at risk.
When person A has gonorrhea or chlamydia and could only have acquired it from person B, and person B is tested, s/he has a positive test only 60-70% of the time; for trichomonas, it's probably only 20%. There are several reasons: virtually all infections clear up without treatment after anywhere from a few weeks to a year, sometimes more; some people receive antibiotics in before testing (either because they get treated for STD but deny it, or because they get an antibiotic for something else); even the best tests miss some infections, and some providers or labs use lousy tests; and some test specimens are mishandled, reducing test reliability. (And no routinely available test detects more than 20% of trich in men and 50% in women.)
If the non-marital partner acquired infection in mid-December and a good test were done today by a knowledgeable provider using a good lab, t1234 probably would be right. But there is no clue as to how long she might have been infected and probably no way to influence what provider or lab test would be used.