How do symptoms even show up? Could there be some pimples on the head of the penis, or is it an STI?…

How do symptoms even show up? Could there be some pimples on the head of the penis, or is it an STI? My friend called me recently, crying her eyes out. She said her husband is cheating, that he has some pimples on his head, and she's itchy and burning down there. I calmed her down, telling her that it could be a yeast infection for both of them. Her husband's probably not been "fresh" lately, and he infected her. She was crying, saying she hasn't cheated. I somehow managed to calm her down. Has anyone actually experienced this? I had a yeast infection twice, with cottage cheese-like discharge and that was it. My husband and I immediately took Fluconazole, I used Clotrimazole suppositories, and my husband applied Clotrimazole cream.