I had unprotected sex this month many times with a friend & he used to have prostate cancer but he doesn't anymore because he had prostate removal surgery. We have feelings for each other but it's more like a fwb. I trust him completely. My question is since we didn't use protection but there's no ejaculation, could hiv or a std still be transmitted? I feel fine but a few days after I had sex I was getting pains in my lower stomach/back and one night I threw up.