Hi, welcome to our forum.
They say love is blind and it's is good that way. However, your own safety is a necessity and we are glad that you are being conscious about it.
Being in a sero-discordant relationship, there are 3 important considerations to make, it is your personal choice to select either or practice all of them together.
1. PrEP: It is a biomedical development that is already playing a vital role in efforts to control HIV transmission.
Unlike post-exposure prophylaxis (PEP), which is taken after a potential exposure to HIV, PrEP is taken on an ongoing basis before potentially being exposed to HIV or before/throughout a period where you know you are going to be having unprotected intercourse or as a measure to be extra careful even with usage of condoms. Some would say it’s similar to ‘the pill’ that women take to prevent unplanned pregnancy.
This can be an important choice for you to make if your partner has not achieved an undetectable viral load, and you don’t always use a condom. If you are using this strategy, you should first discuss it with your prescribing GP, and make sure you understand the timing of the pills.
2. Using condoms consistently and correctly: Always insisting on usage of condoms for vaginal / anal intercourse, make it a point to squeeze the tip of the condom to release the air before using it to avoid breakages. This is imperative to refrain from getting infected if your partner has viral load at detectable levels.
3. ART: Antiretroviral therapy (ART), this works by controlling the replication of HIV in the body. It reduces the virus's ability to make copies of itself. When HIV replication is controlled, the viral load in the blood and bodily fluids decreases, so does the risk of HIV transmission. With successful treatment the viral load lowers to an undetectable levels, this can eliminate the risk of HIV transmission.
ART consists of a combination of multiple anti-retroviral drugs that needs to be taken daily. The power of ART today is so profound that many people who start effective treatment soon after becoming HIV positive will have a near normal life span. One important thing to understand, the viral load should remain undetectable for at least six months before depending on this approach as an effective HIV prevention strategy.
The above stated information is not a substitute for a doctor's guidance or recommendation, you must always work closely with your doctor to understand what works the best in your favour.
Also, the most important point for your peace of mind is that to know his statue. Is he getting ART drugs and keep his viral load as undetectable ? You may read the recent research results about U = U. (Undetectable = Untransmitable)
Not everyone should date an HIV positive partner and I'd say anyone with a history of HIV anxiety would be best not to. Keep that in mind. It may not be wroth it if you will have constant worry. You will not get HIV from having oral sex with him. no one gets HIV that way in real life. Saliva has enzymes in it that break down the virus and air inactivates it as well. Use a condom for penetration. Otherwise, touching and rubbing will not transmit the virus because again, air is present. But this may not be a good relationship for you psychologically. If you continue, I'd visit doctor for education on the subject to help put your mind at ease.