hiv is very low transmission through oral sex - there have been several studies following partners where one person was positive and the other was negative. if they only engaged in oral sex the risk to the hiv negative person was extremely low if not close to zero. so be assured that you are ok but since you are sexually active make sure you get follow up hiv tests at least yearly or more frequently if you are having vaginal or anal sex. . hiv is not the only std in town and is much more difficult to catch than the other ones. so get checked for gonorrhea herpes syphilis and chlamydia while you are doing your yearly exam.
could i have gotten hiv from having oral sex with an hiv-positive partner?