HIV is a terminal illness for which there is no cure. HIV may lay semi-dormant in your system for years before acute symptoms appear. It is too late to be tested once sysmptoms do appear, so if you think that you might have come in contact with this virus through sex or sharing needles, or touching potentially infected bllod or boldily fluids, get tested as soon as possible.
The only way to completely avoid catching HIV is by not having sex or sharing needles, two activities which may pass bodily fluids between an infected individual and one who is not. Any contact with infected bodily fluids (blood, mucous, semen) is a chance that you might catch the virus.
WHAT ABOUT CONDOMS?
Like most things, condoms are not 100% effective at preventing pregnancy, nor in preventing the spread of STDs like HIV.
Most condoms are made from latex, a material that has, on a microscopic level, naturally occuring holes. The holes can allow infected semen, blood, and other fluids to be passed from one to another. Condoms do slightly lower the risk of the spread of some STDs and HIV, but are not a 100% effective solution and should not be depended upon as a suitable level of protection to stop the spread of HIV.
WHAT ABOUT PULLING OUT?
Just because you do not ejaculate when having sex (vaginal, anal, or oral) does not mean that infected boldily fluids were not shared. Also, just because you did not ejaculate inside your partner, does not guarantee you did not share bodily fluid. Pre-cum, blood, and mucous can all, potentially, carry the HIV virus between partners.
Safe sex is a myth. We do not seek HIV positive people to be complete abstinent, but the risk of sharing HIV through sex is extremely high. Protect yourself!