Couples where one is HIV-positive and the other isn't are called serodiscordant couples, and they have long worried about the possible transmission of HIV. The first thing you need to know is that you can have a happy and healthy relationship regardless of your status. But like all relationships, it requires work and commitment, because love does not conquer all.
Still, the amazing news is that if you are HIV-positive, on medication, and have suppressed your viral load to undetectable levels; you literally have zero chance of giving your parnter HIV, no matter what you do in, or out, of bed.
However, if you aren't on meds, or you haven't been able to lower your viral load, you can still avoid transmitting HIV. Your HIV-negative partner should talk their physician about getting on a pre-exposure prophylaxis, or PrEP; research has shown that the prevention protocol is 99 percent effective in preventing the transmission of HIV infection in the negative partners of HIV-positive gay men.
Unfortunately not everyone (even doctors) are aware of these two remarkable developments, so you may still face stigma as a serodiscordant couple. If so, consider seeing a counselor who specializes in coping with HIV. HIV-negative partners sometimes encounter disrespect from friends and family members when the poz partner's status is revealed. A counselor can help you work through those kinds of issues and communicate to each other your anxieties, fears, and needs.