Hi there Dannie, thanks for coming to us with these questions, it does sound like this doctor shared some misinformation with your boyfriend, or explained himself so unclearly as to cause confusion and misinterpretation. Either scenario is concerning, and of course caused undue stress and concern to you and your boyfriend, so I'm sorry that you had to deal with that.
What you learned in school is correct, you can only contract HIV from someone who is already HIV+
and is not taking medications to manage their viral load (these days, people with HIV can take medications which render their viral load to be so small that it is undectible, and this prevents them from being able to transmit HIV at all, as long as they keep up their medication). It is not possible to spontaneously develop HIV.
Because your boyfriend will have a healing surgical wound on his penis from circumcision, there is an increased risk of contracting an STI like HIV if he were to have unprotected sex with
someone who already had HIV and was not taking medicines to prevent them being able to transmit it, because the wound may open from the friction of sex (which is why people who have circumcisions do have to abstain from sex for a while, so that they can heal from the surgery, and the friction of sex (including masturbation) would impede this. You and your boyfriend can read more about this
here).
With regards to multiple sexual partners, again, the risk of contracting HIV is only present if one of those partners have HIV. Sometimes having many sexual partners can be described as whats called a "risk factor" for HIV, but that is about the risk that the person is not asking their partners (or partners being dishonest) about their STI status and/or insisting that their partners are up to date on their STI checks, its all about the
odds that eventually someone they meet and have unprotected sex with might have HIV. Like any risk, this can be reduced by engaging in good risk management, like talking to partners about the STI status, wearing condoms, taking preventative medications like PrEP if you do plan to/there is a high chance you will have sex with an HIV positive partner or persons who's HIV status you do not know. Hopefully this helps explain why having multiple partners can't
spontaneously cause HIV to be generated in someone.
Finally, I wanted to touch briefly on language, specifically the term "clean" to indicate that someone does not have an STI. This kind of language is quite harmful, suggesting that someone with an STI is "dirty" and deserving of being seen as somewhat "lesser" than other people, which is not the case. These kind of stigmas often prevent people from getting tested because they're scared of what having an STI would "mean" about their character, even though it's just like getting any other infection, like bronchitis or a cold, which just needs treatment to get better, and to rest up and take precautions to not spread it to other people until you're better. However instead of doing just that, people might have an STI and engage in unprotected sex with it because they "don't want to know", which is counter to a healthier life for them and others. Essentially, the stigma around STIs is one of the reasons there is the risk factor that we discussed above, because it makes people scared to get tested, and judged, so they don't discuss nor are honest that they know their STI status (or might lie about it) and so engage in unprotected sex and spread the STI, rather than take risk prevention steps and/or get treated. A better way to communicate an STI status would be to simply say something like "I am up to date on my STI tests, and don't have any".
Hopefully this answers your questions and has helped clear things up! I am going to put some articles below that go into more depth explaining what I outlined above about HIV, which you might find useful to read, and if you have any further questions about this, please don't hesitate to ask:
Recommended Useful Articles
