Welcome to the forum. I'll try to help. By the way, your profile shows you as female; you might want to modify it.
You describe a very common yet difficult clinical problem in men with gential symptoms: do you have an STD or not; if so, which one; and if not, what is it? Urethritis and prostatitis (non-STD) symptoms overlap and these conditions can be difficult to distinguish from each other. STDs rarely cause the subtle sort of symptoms you describe. Mildly symptomatic urethral infections usually have scant discharge, not a burning sensation, and the normal appearance by a trained practitioner plus the negative chlamydia and gonorrhea tests also are reassuring.
Still, it is conceivable you had an atypical case of nongonococcal urethritis (NGU), which could have been acquired from the oral sex part of your commercial exposure last June. For that reason treatment with azithromycin was not unreasonable. The improvement in symptoms also suggests something was there. (But are you sure that's the drug you were given? Ten days is very atypical. Maybe it was doxycycline?)
NGU not uncommonly recurs after treatment, in which case symptoms usually respond to re-treatment with the alternate drug (azithro if initial treatment was with doxy, and vice versa). Or, as you correctly suspect (the last part of your question), it probably is indeed possible you have been reinfected from your regular partner.
Having said all that, all your symptoms are equally compatible with prostatitis, and the urine dribbling and testicular discomfort are much more consistent with prostatitis than NGU or other forms of urethritis. So all this may be merely a coincidence with your commercial sexual exposure. So if and when additional treatment is tried, she also will need to be treated. You should discuss these issues with your NP.
Unfortunately, it can be very difficult to sort these things out. My advice is that you discuss all this with your NP; or perhaps a physician (e.g. urologist). If it would be helpful, you could print out this discussion as a framework for discussion with your provider(s). Somewhere along the line, it may make sense to try another round of antibiotic treatment, including treatment of your partner.
To close with a word of encouragment: nonchlamydial NGU and garden-variety prostatitis are generally believed to be harmless, both for affected men and their sex partners. This is primarily an issue of comfort, not one that is likely to result in anything serious like infertility, urethral stricture, or complications in your partner.
Best regards-- HHH, MD
Apologies, I misrepresented the duration. As you suggest, I received a single dose. The 10 day duration related to abstinence from alcohol as the treatment occurred.
This doesn't compute. Neither drug is in the penicillin category and both are commonly used in penicillin allergic patients. Azithro is very long acting and is normally given in a single dose for chlamydia or other STDs; I've never heard of it being prescribed it for 10 days.
Thank you for the response. As explanation for the Zithromax prescription rather than doxycycline, I have an allergy to pencillin.