In the 20 years of intense hiv research, there have been no documented cases of transmission from recieiving oral sex.
The facts -
1. Saliva does not transmit hiv
2. Saliva has properties which inactivate the hiv particle
whatever spin you may wish to place on it, such as any traces of blood present etc., the mouth is an extremely inhospitable place for an extremely fragile virus. And, no one has ever been confirmed as having been infected with hiv this way. You won't be the first.
Please visit aidsmeds.Com, and post in the fears forum if you want confirmation.