HIV is a virus. It's contagious. If it's not there, you can't get it. You can only get it from somebody who is infected.
If a person has it, you can get it with any body liquids except spit. Means, you can get HIV if blood of a HIV-infected person gets inside your body - through a wound for example, with a blood transfusion or with a non-sterile injection (often happens to junkies) . Or if sexual liquids of somebody who is infected get into your body. That is, through unprotected sex. HIV is not transmitted by kisses though, because the concentration of viruses in spit is very low, normally. Pleas note that HIV has a very long incubation time. Somebody can be infected with the virus for 5 years and be completely healthy. AIDS comes later.
You can, of course, get pregnant if you have unprotected sex. Even on your period. It's not highly probable, but it's possible. Or you could get infected with other diseases (mycosis, pubic lice, tripper, syphillis, hepatitis) - but again - only if your partner has those.
Be safe the sheep
HIV is only transmittable through people who actually have the illness. It doesn't just magically show up. If neither of you have it, then unless you're both have sex with other people, it's pretty unlikely that you'll get it.
No, at least one partner has to have the disease. However there are lots of other nasty STD's which is why condoms are such a good idea, as well as avoiding an unwanted pregnancy.
No. But you know what you could get? Pregnant. And given your obliviousness, it would be a very bad idea for you to reproduce. Spare the world and use a condom.
If neither of you have it, you can not infect anybody. Obviously you could get pregnant.
