I don't understand. Do you think you get AIDS because you have 2 partners? or because you have sex on the beach? I don't get it. But if you do think that, please read up here, this may educate you somewhat: https://www.who.int/news-room/fact-sheets/detail/hiv-aids
TL;DR: AIDS is a virus, you have or you don't. It's not like a counter that fills up with the more and more sex you have and then BLAM! you get AIDS. You can have sex once and get it, or you can have daily orgies and never get it (although of course the latter exposes you to a higher statistical risk)