If Magic Johnson really has HIV then why wasn't his pregnant girlfriend when he announced it have it too?

When Magic Johnson announced to the world that he was HIV positive in 1991, he was a single man but Cookie was his girlfriend at the time and she was already pregnant with Earvin III. Two months later she married him. How did he impregnate her and have unprotected with her still marrying him, if he was HIV positive? Does she have super immunity? And at the time there was only 1 drug on the market for HIV and everyone was dying within months to a couple years from the time of diagnosis but he's made it to 19 years. SO what's the deal/truth? It usually takes a few months to even test positive and then it's not like on the same day he got tested the moment the test would show positive and not like in the meantime he wasn't having considering he got her pregnant so why did his girlfriend and her fetus remain negative? And at the time with only 1 drug that didn't really help, why would she have still married him esp. since she was negative (and condoms can break and he prob had to have had gay to get it considering he's never said it was from needle use and he was never tested positive for needle drug use considering as an NBA player they'd catch it)