I cannot speculate further. It is up to you whether you want to gamble with your wife's health. The odds you transmitted anything harmful to her are low, but they are not zero. It's your call.
Thanks for your help again. Sadly, perhaps, my wife thinks my problems are related to her repeated yeast and urinary tract infections and/or her herpes infection which hasn't been active for years.
I have been very reluctant to confess because, from the outset, my infection has been atypical: no discharge or symptoms for over 4 weeks after unprotected sex; 5 days for discharge to disappear after treatment with Azitheromycin; now tests negative for Gonorhoea, Chlamydia, Syphilis and HIV (probably didn't attempt to culture Mycoplasma). I suppose something like Mycoplasma is looking more likely now by a process of elimination but I do still wonder if this could be something else and maybe not even an STI.
Most likely the lymecycline would have protected your wife against the whatever was causing your NGU. (Nongonococcal urethritis/NGU is the same as nonspecific urthritis/NSU.) Not necessarily, however. About 10-20% of NGU cases are caused by a relatively newly discovered organism called Mycoplasma genitalium, which responds to azithromycin but not the tetracyclines.
Therefore, most likely no harm will come if you wife doesn't get additional treatment. However, there is no guarantee. For maximum safety, she should also be treated with 1.0 g azithromycin. Most likely you'll have to come clean with her about the reason, but she probably knows anyway. Most women know or suspect the truth when their husbands tell them to see a doctor without saying the reason.
Good luck--- HHH, MD