Are u less likely to contract hiv from vaginal entercourse if u never had any std compared to unprotected anal sex if one partner is hiv positive?

Depends: For males, contracting HIV from anal sex is much more likely if he is receiving than giving the anal sex. In the case of vaginal sex for the male, he is less likely to contract HIV than the female. For females, her chances are greater with vaginal than anal sex, but much greater overall than the male, especially if he ejaculates within her unprotected by a condom. Other stds play no role.