This answers all of your HIV questions, and if you can think of any more just reread about the 3. You had zero risk therefore testing is irrelevant to your situation because you had zero risk. HIV is a fragile virus, which is instantly inactivated in air and also in saliva which means it is effectively dead so it can't infect from touching, external rubbing or oral activities. It doesn't matter if you and they were actively bleeding or had cuts at the time either because the HIV is effectively dead.
Only 3 adult risks are the following:
1. unprotected penetrating vaginal with a penis. Only the head needs to be covered, so if that happened it is protected and there is zero risk
2. unprotected penetrating anal sex with a penis. Only the head needs to be covered, so if that happened it is protected and there is zero risk.
3. sharing hollow needles that you inject with.
The only way to get HIV is if you did one of the 3. The situation you describe is a long way from any of these 3.
Even with blood, lactation, cuts, rashes, burns, etc the air or the saliva does not allow inactivated virus to infect from touching, external rubbing or oral activities. This HIV science is 40 years old and very well established, so no detail that you can add to your encounter will change it from zero risk. Because of all the research statistics, doctors have calculated the risk from what you describe to be less than that of being hit by a meteor, therefore no one will get HIV from what you did in the next 40 years of your life either.
If you didn't have one of the 3 then you are just worrying about your own hiv theory - which is unrealistic for you to think that can become reality - so you should move on back to your happy life instead.
Your tests were a waste of time since you had zero risk. It is abnormal to test repeatedly for the same disease, and since you had no risk it will be hiv phobia if you test again.
You are not making sense since you agreed that you didn't have exposure. Your distrust of the science has caused you to test repeatedly for no reason, while claiming that your theories are being "extra cautious." The science is 40 years old yet you question it and only trust your own science fiction theory that somehow you have discovered hiv transmission issues that all the other scientists missed. Despite having no medical research training, the only science you believe in is your own which is unrealistic for you to do.
Your problem is not disease it is fear of disease, and at this point your anxiety and overtesting issues are a mental issue that might be best to work on with a therapist, since no one here can provide one on one.
As pointed out by ANM you never had a risk to begin with and testing was not necessary. That faint line that you are speculating isn't an indication of false positive but an indeterminate result that occured due to incorrect handling or worst case; due to a technical glitch.
Nothing that you described points towards any scope of HIV transmission. You must forget about this incident and look forward to your new relationship with out any fear and worry. Should you feel that you are unable to get over this irrational fear see a therapist.