However, there are many ways to reduce risk of transmission, even for an uninfected person in a sexually active relationship with someone who is HIV-positive.
Many studies have been conducted on serodiscordant couples, meaning that one partner is HIV-positive and the other is HIV-negative.
There are three primary considerations that you'll likely be navigating as a couple: Keeping the HIV negative person uninfected, managing potential power differences, and the psychological/emotional impact of life-threatening illness.
So if you are not partnered, you may still want to use a condom whether you are HIV-positive or negative.
But if you are partnered, then that is between you and your partner.
In these situations, the HIV negative partner might intentionally make the positive partner feel (financially or otherwise) indebted to her or him for being in the relationship, may exploit the status of the partner to gain access to resources, or may be even disrupt the positive partner's medication regimen, endangering her or his health.
The reverse can also occur if the HIV positive person behaves abusively towards the negative partner, using their status as a means to control her or him.