if the problem persists or recurs, give the alternate drug plus metronidazole (Flagyl) or tinidazole (Tindamax) to cover trichomonas;
and for still more recurrences,
moxifloxacin, apparently the best drug for M. genitalium. If your treatments have been different than this, discuss it with your doctor.
Some cases at this stage may be due to prostatitis. Infection due to unusual bacteria may need to be checked out.