Why you should tell. (Only if you have proof).
People will have opinions. Mostly the guilty will try to deter you from doing what your heart is telling you.
Of course some posters are well meaning, but if any one tells you that you shouldn't tell. Then they are wrong, and there are many reasons why you should, but here's the only one you really need.

Remember that there is a difference between HIV and AIDS. An HIV positive person is just that - they have the virus in their body. AIDS is the end stage of the HIV infection. Plainly HIV is the virus and AIDS is the disease caused by HIV. A few weeks after the virus enters the body, some people have flu-like symptoms such as fever, body ache, and headache which disappear after awhile. Remember that all HIV positive people do not experience these. Many people with HIV show no signs at all of infection until they develop AIDS. The only way to truly know is by getting tested and remember the "window period" mentioned above. It can take months to years to develop signs of infection and during these years people can remain asymptomatic. About half of the people who are HIV positive develop AIDS within ten years but this can vary immensely depending on treatment with drugs, etc. If you suspect that you have been exposed get tested, Even though this is scary it is much better to find out sooner than later for many more treatments are helpful earlier on and some can prolong full blown AIDS indefinitely.
NUFF SAID,