Hello Rose, Welcome to Healthcare magic forum. Any unprotected sexual intercourse with an hiv positive person , puts you at a risk of acquiring hiv infection even if the ejaculation has not taken place. HIV transmission from one person to another through sexual contact can depend on any of the following factors: 1.Unprotected (without a condom) sex with multiple sex partners. 2.The presence of other STIs (sexually transmitted infections), especially in the case of genital ulcers and inflammatory STIs. 3.Trauma (or bleeding) during sex, as well as menstruation. 4.The viral concentration (or level of viral “load”) in the blood , or body fluids of the infected partner. 5.The phase of infection. HIV is much more contagious in the acute stage or when the immune system is suppressed (this is also then an indication of a high viral load and a low CD4 count. So without knowing the status of the stranger the exact risk you face cannot be quantified. It may vary from a minimum of 0.08% to 0.555% per exposure or more . In your case since there is history of mucosal injury and sexually transmitted infection the risk may be 20 times more than in the absence of injury and infection. Please do not rely on numbers as such exposure may be no risk if the stranger is hiv negative to a high risk if he is hiv positive.Also remember that in future, use condoms to protect yourself against STI and Hiv. To be on the safer side, do get yourself tested as soon as feasible and contact your physician for appropriate guidance depending on the results. Hope I have answered your query. Wishing you good health, Regards