There is no set time for the period of time one should wait between curing a yeast infection and having unprotected sex. First of all, it would depend on how severe the infection was, and whether or not it's a yeast infection or a Candida infestation because there's a huge difference.
If I had to guess, I would say that, if you're 100% certain that the infection is cured, and you've had absolutely zero yeast symptoms for at least one year, then it's probably safe to have unprotected sex.
