My girlfriend my semen and then shortly got strep throat. however, a friend recently had strep throat and she drank out of the same cup that his girlfriend was drinking from. am i the cause of her strep throat?

Hard to guess: Throat pain can be from a strep throat infection (antibiotics needed), a cold or influenza (antibiotics usually not used), or from some other cause such as allergies or irritants. Usually, a person sees the doctor (call first) if the sore throat is bothersome, recurrent, or doesn't go away quickly. COVID-19 infections tend to have cough, whereas strep usually lacks cough but has more throat pain.