Wow... This is heartbreaking on so many different levels.
I guess the first and most important thing to address is that this dude is NOT correct in stating that it has been proved that oral sex is 100% safe and that a negative partner cannot get HIV from oral sex with a positive partner. THIS IS COMPLETELY FALSE!
There is NO SUCH THING AS 100% safe. Nor have there been any studies or research or data which suggests this.
It is important, however, that you keep in mind that no one here can say whether or not this guy is actually LYING to you. It's obvious that we can't read his mind or accurately make assumptions at his intentions. He may simply be misinformed and means no harm.
Unfortunately, the other side of the coin is that if he IS lying, he's despicable and dangerous.
I do not envy your position. You have to determine what's what and decide upon your course of action. You have some difficult choices to make.
Let's touch on a few things of some importance that might at least give you an idea of where to start. You will need to commit yourself to some time and research if you intend to pursue this relationship. There are some things you will need to keep in mind.
1) You have asked one of the most common and also one of the most difficult questions with regard to safer sex and HIV transmission: the question of how safe is oral sex. You will hear a wide variety of responses to this. Look in the CFS archives and read the thread about oral sex safety. Pay special attention to what Dr. Danny writes there. TRUST HIM. You can also go to
www.thebody.com and look through the site: it's rather large, prepare to spend a bit of time reading all you can. The CDC website also has some decent info, but it's kind of been "sanitized for our protection" by the government, so it isn't as explicit as we might hope. You can go to online HIV+ chat rooms and POLITELY ask the occupants if they will discuss some issues with you. One caveat: these guys are NOT always in chat to discuss their disease at length -- sometimes they just want to have some good conversation about other topics. If you meet with resistance, just move along. You may find a few guys willing to chat privately with you.
2) Rest assured that you CAN get HIV from oral sex. Exactly how likely this is has never been determined to any degree of certainty, but we DO know that oral is "less risky" than anal. Probably a LOT less risky. But it is NOT "100% safe" as this guy suggests it is. DO NOT BELIEVE THAT FOR AN INSTANT. You MUST be aware that you ARE taking a risk by having unprotected oral sex. If you choose to accept that risk, then you have made your own choice in the matter. But do not be mislead.
3) Swallowing is MOSTLY a moot topic. It is exposure to semen in the oral cavity where the risk occurs. Spitting or swallowing doesn't matter much. Stomach acid will kill HIV, but if infection is to occur, it is going to happen in the mouth. Spitting probably also doesn't matter much. Yet these things are relative. There are many, many factors which come into play here. How high is the viral load in the semen? Has there been repeated exposure? How healthy is your mouth? Has the cum been in your mouth a "long" time or have you spit or swallowed more quickly? These things matter a lot -- and they also matter very little. Sucks, doesn't it? There's no definitive answer here, except to say that YES, a risk DOES exist -- it is lower than unprotected anal, but NOT completely safe by any stretch of the imagination.
4) HIV + and "healthy" is a term often used today. It means a person is not suffering yet from symptoms. That's wonderful. It usually also means that his viral load is pretty low, thanks the the medications. The lower the viral load, the better the chance that a negative person would leave an encounter and remain negative. But this does NOT mean there is a time when HIV + people are NOT contagious. HIV is ALWAYS contagious. ALWAYS. DO NOT FORGET THAT! HIV is MORE contagious immediately after infection, when the virus is multiplying rapidly in the body, and also at the end-stage of disease, when the immune system is nearly destroyed. In the interim period, there will be fluctuations, but there is NEVER a time when there is NO risk -- you can ALWAYS still get it no matter how small the viral load is. Viral load readings mean that conventional testing cannot pick up much virus at all -- but that does NOT mean there is NO virus there. It is always there -- just in very tiny amounts per any given sample size. Understand?
5) You may think he knows a lot about his disease, but apparently he has missed a few very important facts, especially with regard to the safety of his partners. Just because he may have been involved in studies or clinical trials or whatever doesn't make him a doctor or a scientist. When you live a disease, it is best if you educate yourself about it so you can live a better life and take an active role in your treatment -- probably he has experience with this. But it doesn't mean he knows everything.
6) He was at least honest with you about his status. That's good. It lends some credence to the possibility that he is NOT purposely trying to trick you -- but he IS still incorrect to state that oral is 100% safe.
7) You and he need to have some LONG talks about all of this. If he's unwilling to do this, he's not worth a relationship. If he cares about you, he should be MORE than happy to put you at ease, get educated together with you, and make sure YOU remain safe and healthy at all times. Anything less is unacceptable.
8) NEVER, EVER allow yourself to feel so much pity that you do things which jeopardize your own well-being. Though it may be admirable of you to understand that being HIV + doesn't make someone a pariah, you cannot let your desire to perform altruistic acts bring you harm. Kindness and understanding and compassion are wonderful qualities to share and desire -- but you need to love YOURSELF, too. You must think of your OWN health and safety at all times. DO NOT LET POLITICAL CORRECTNESS DICTATE YOUR SEXUAL BEHAVIOR.
9) If you get involved in this relationship, you will need to prepare yourself for all sorts of small and not-so small details that come along with HIV. Right now, most likely you are not involved with the day to day details of what this disease is really all about. But you soon will be. This can be mentally difficult to handle sometimes. Are you prepared for that?
10) Also, if you do get involved here, you will need to be tested for HIV on a regular basis no matter how safe you think your sexual acts may be. Are you ready for that, too? I'd personally recommend testing every three to six months when involved in a sexually active relationship with a poz guy. Can you handle it?
11) Being just friends isn't necessarily a bad thing, either. If it doesn't work out with the two of you for whatever reason, it doesn't mean you must exit this man's life and never see him again. You can still be a supportive and loving friend to him. Just keep that in mind. Everyone can use a new friend from time to time.
12) Don't jump down his throat and accuse him of lying -- I'm repeating that we can't judge his actions based on what you've written here because that's very important. Sit down and talk together. If he takes great offense at the suggestion to do so, I'd smell a rat and be extra cautious.
Summing it up... YES, you can get HIV from oral sex and exposure to semen. It is best to NOT expose yourself to semen at all if you are going to have unprotected oral sex. End of story. If you DO expose yourself to semen, you ARE at risk. Swallowing, not swallowing -- probably doesn't matter at that much. It's the semen in the mouth that makes the most difference... most likely.
It's good neither of you have rushed into things so far. It shows caring on both sides. It shows some intelligent reasoning going on. Both of you should be commended for that.
Continue in the quest for further knowledge -- BOTH of you. He IS wrong about what he told you, but yes... oral is LESS risky than anal. That's about the only definitive thing we can say.
Best of luck to you both.
There are lots of folks here who will speak to you privately via email if you have specific questions, myself included. What I wrote here is kind of basic and repetitive; this comes up often. Details can be supplied, but don't expect rock-solid numbers or statistics for every given sex act. These numbers, while they CAN be found here and there, don't mean shit when put to the real world test of highly flexible human sexuality. I'm going out of town on Sunday, however, and cannot respond to email until the end of next week.
Take it easy.