Yellow discharge my boyfriend doesn't have std or hiv is this pregnancy or infention. negative blood test?

Vaginal Discharge: Vaginal Discharge is an indiction of an infection. It is either a fungal or bacterial infection. HIV is a virus and would not cause a vaginal discharge. Other common STDS would be gonorrhea and Chlamydia and there are tests to rule this in or out. But, most yellow vaginal discharge is other common bacterial or fungal infections and are not STDs. They are not in any way pregnancy.

Get checked out: Yellow vaginal discharge often indicates infection, either STD or other causes. The STD tests in males are very good, but not perfect, and some STDs in men don't show up in standard tests (e.g. nongonococcal urethritis, NGU). So you need to be professionally checked in person. See your usual reproductive health doctor or clinic. But don't worry about HIV. It doesn't vaginal discharge.