In the beginning, an HIV positive person does not show any conspicuous symptom either. Some of them go in for arranged marriages and gleefully infect their innocent ignorant brides. In India, all you have to do to get married is declare your salary. In orthodox circles, the comparing of horoscopes may be necessary. But nobody will ever ask you for your medical reports.
Marriage brings in discomfort and disease.
The brides turn cynical, wondering which heaven arranged so much of misery for them.