I recently had sex with a HIV + male. I was the top he was the bottom. As we were having intercourse the condom broke. I knew it broke but I continued. After I told my partner what had happen and he knew it also, but told me that cause I was the "top", our act was consider Low-Risk. Is this true, and what is considered low and high risk? Thank you
Good question, and, like many good questions, difficult to answer.
Risk is relative, so using "high" or "low" risk is not always useful. For instance, compared with being with a bottom in anal sex, being the top could be considered low risk. However, compared to unprotected oral sex without ejaculation, being the top in unprotected anal sex could be considered high risk. There are multiple variables that could be considered in each encounter that change the relative risk as well (how much fluid were you exposed to, how much virus were you exposed to, what was your immmune response, etc.).
Risk is also based on a person's subjective interpretation of risk. One person might consider performing oral sex on an HIV infected man high risk, while another might consider it low risk.
So, high or low risk might not be useful in the situation you describe. The facts might be more relevant:
A person who is the receptive partner in anal sex is considered to be at a greater risk for infection than the insertive partner. The insertive partner is not without risk if no condom is used.
Condom breakage rarely results in HIV transmission. The lack of condom use is more likely to be a factor in transmission.
The odds of transmission in one episode of UNPROTECTED anal sex with an infected partner are much lower than many people think. Figures for the risk of infection per episode of unprotected insertive vaginal sex with an HIV infected person (it's not anal sex, but some comparisons could be drawn) are less than 1%.
Your partner's viral load is likely to have an effect on transmission. If his viral load is very low/undetectable, transmission is less likely. See http://www.thebody.com/Forums/AIDS/SafeSex/Current/Q93372.qna.