What are the chances of getting an STD if I had unprotected sex but he did not ejaculate?

It could be prostatic fluid as mentioned by Dr Winston, or possible infection with Candida, chlamydia, gonorrhoea or herpes simplex virus. You will need a full STD workup or urine and blood tests to ascertain the cause.

One has to be careful in interpreting the urine analysis. To be accurate it has to be a clean mid-stream urine specimen. This may be difficult to collect at times. What happens very often is the urine will pick up White blood cells which are part of a vaginal discharge and gives the false impression that it is a urinary tract infection. A specific test for vaginal infection must be done if there is an associated abnormal vaginal discharge. The Trichomoniasis comes from the vagina rather than from the bladder.