On the topic of Hiv and mutation and stuff.
The thing to remember is that Hiv and most other viruses for that matter, don't breed with other organisms.
They replicate using their own genetic code.
Now, mutations can and do happen - these are 'accidental' mutations that occur when the virus is copying the pattern of its own DNA into a host nucleus.
Imagine a printer that is running out of toner - its prints out a picture that is slightly faded, then tries to scan it, and print it out again. Eventually, the picture becomes completely unrecognisable, because of the continuous distortions during the print process.
Picture of a picture of a picture of a picture etc
Most of these mutations are completely pointless and random - eg: They might actually be detrimental to the next generation of the virus.
Others, can be beneficial.
The beneficial ones are the ones that lead to med resistance.
This works on that time old saying that is 'Survival of the fittest'
When you go on meds, you kill off 99% of the virus through attrition. (The meds don't actually kill the virus, but rather interfere with its ability to replicate, so the virus basically dies off due to 'old age' and the replication rate decreases - this forces the hiv population down, we should do this to some benefit scroungers in the uk. lol)
1% remains, albeit suppressed by your meds - a low replication rate is still present.
If you stop meds, and that 1% starts replicating again, you end up with a 100% population of hiv virus in your blood stream, that were directly descended from the 1% that had at least 'some' tolerance to your hiv meds.
You go from <20 per ml to >100000 per ml.
The danger of med tolerance is that you are then repeating the step that reduced 100% to 1% when you resume meds.
But each time you do that, you are putting the virus through its paces, forcing it to derive 'accidental mutations' that are beneficial to its survival.
Eventually, after many repeated cycles of stopping meds - your virus will have mutated (through natural selection)
This is why Doctors will advise you that starting meds, stopping and restarting is dangerous.
In some cases, if you are having trouble with adherence, Doctors might advise you to stop taking the important HIV meds, until you have got used to a level of adherence to taking meds on a strict regime.
Eg: They don't want you to lose the ability to take the important hiv meds.
Stopping meds once, until you get your head sorted out, and then resuming is safer than start, stop, start stop, start stop etc
So in this regard - HIV cannot breed.
If someone else with the same hiv type and subtype has sex with you, I don't think its likely they can necessarily infect you with hiv that then changes your own strain.
That being said - if they are carrying a resistant strain, it might be possible for that strain to get a foothold in your system.
If your HIV type and subtype matches the person who fucked you and bred you with a resistant strain, the doctors won't really have visibility of you catching a resistant strain, they will just see that your HIV has become resistant. They will just say that its down to dumb luck or perhaps query your adherence.
They won't be able to tell from a blood test that you acquired the resistant hiv from someone else, because their type and subtype were identical to yours.
Its like looking for a black cat amongst a room of black cats.
If however, you got fucked by someone who has a different HIV type and subtype, I have heard that there is a chance you can acquire their type and subtype, in addition to your own.
Eg: Dual Infection etc
I don't know if there have been recorded cases of it - years back when I first became poz, I looked it up, and it was kinda used as a cautionary tale.
People trying to use terror tactics to scare you out of making a super bug by fucking about.
Back then, it hadn't actually happened yet.
If its happened in the last few years - who knows.
In this case- doctors should be able to tell if you are dual infected, as its like finding a white cat thrown into a room of black cats.
So They can detect the presence of Hiv Type 1 plus Hiv type 3.
(Type 3 I think is prevalent in Africa? 2 in asia? not sure)
So... The last part of your question: around meds and safety of fucking about.
There is always risk when you fuck raw.
You have discovered the outcomes of some of those risks.
The risk of fucking while poz with other people who are poz, is that you may not know their viral load and the meds they take.
For instance: Someone who has been poz for 20 years, might have exhausted dozens of treatment options, he might be full blown aids with a viral load through the roof.
If he fucks you, and floods your guts with his charged load, he might end up stealing a few treatment options from you, because he will have passed on his med resistant strain. Remember, if he is the same type and subtype as you - the doctors will just assume your virus got the better of you. They wont know any different, and its not like they can do anything about it anyway.
If however, he is on same meds as you, undetectable and you are undetectable and on meds - research suggests there is little to no risk.
In fact, him being on meds and undetectable is essentially the same as being neg when it comes to transmission rates.
Being on meds yourself at the same time is just an added bonus.
Im not advising any particular strategy-
we arent on this website because we like playing safe...
I like it raw as much as everyone else... possibly a little more. ;-)