Hello First of all I want to tell you that you are in contact with your friend form last 4 years and had sex 10 times ( unprotected ). Since you are in relationship from 4 years , if your friend wound have been a patient of HIV infection , this disease may have infected you and symptoms may have developed . Now the answer of you question Is a risk of getting HIV . HIV infection is predominantly a sexual transmitted disease worldwide. Although ~42%of new HIV infections are among men who have sex with men ( you are not an exception ) but both of you are old partner and know the status of each other so need not to worry. Now about the ANAL INTERCOURSE & HIV risk. There is a stron association of transmission of HIV with receptive anal intercourse,probably because only a thin , fragile rectal mucous membrane separates the deposited semen from potentially susceptible cells in and beneath the mucosa and trauma may be associated with anal intercourse . Anal douching and sexual practices that traumatize the rectal mucosa also increase the likelihood of infection. Two ways of HIV infection: 1 Direct inoculation into blood in cases of traumatic tears int he mucosa 2 Infection of susceptible target cells, in the absence of trauma . So this is the risk . Read above mentioned and you will get your answer.