I am 40 years old and have suffered from bouts of prostatitis a few times. I have not had an intimate life for many years. Now, I am having an intimate life with one person, who is clean as well as I am. After vigorous sex, I am having frequent urination, especially at night. I was wondering if vigorous sex can irritate me to bring this on. There is no blood in urine. I had a dipstick urinalysis a month ago and was cultured. All came back negative. But, I have low back pain. Also, my SG was 1.008. Is that low? Ay girlfriend was told that she has a UTI and is susceptible to UTI during sex. Is it something that can also affect me? Because, I am peeing a lot.