Hello Thanks for query. Burning sensation after unprotected sex is mostly due to UTI secondary to allergic reaction to vaginal secretions of your female partner. Please get your routine urine test and urine culture done to find out the organisms causing this infection and antibiotics to which they are sensitive to. Please take broad spectrum antibiotics like Cefexime along with urinary antiseptic like Nitrofurantoin twice daily and urine alkaliser thrice daily.Later on switch on to appropriate antibiotics as per culture report. Get the prescription of medicines from your family Physician. Ensure to drink more water.To keep your urine dilute This will help to control dysuria. Ensure to wash your genitals with warm water twice daily Ensure to avoid sexual encounters till it heals up completely. Dr.Patil.