If a person who is HIV positive has sexual intercourse with another HIV positive person does it affect them?

It can yes. There is a phenomenon known as "swarming". Its the replacement of one strain of HIV for another more virulent one.
Possibly. Hiv infected individuals often carry other sexually transmitted infections such as gonorrhea/chlamydia/hepatitis b/c, trichomonas, bacterial vaginosis etc, so those can be transmitted. Although, the most prevalent viral type of HIV is 1, there is also type 2 HIV virus that is prevalent in certain parts of africa and is not typical for north america, but coinfection is a possibility, albeit rare.

Related Questions