Typically I open my replies with a statement of something like "welcome back to our Forum" but I cannot say that in your case. It troubles and worried me that your anxiety/guilt/shame over your single recent encounter seems to have consumed your thoughts and actions.  In preparing to respond to your question I see that virtually all of them have already been answered.  To repeat the question and expect a different answer is a waste of your time and ours.  The answers will not change.  No less than Albert Einstein said that one definition of insanity is to ask the same question again and again and expect different answers.  Neither my, nor Dr. Handsfield's responses to your questions are going to change.

That your partner was having sex with an African man does not change the answers to your questions.  Your exposure was very, very low risk and your tests effectively prove that you were not infected.  Your concerns about HIV-2 are misplaced- even in West Africa where HIV is most often seen, it is a minority of infections and, as Dr. Handsfield has already told you, the test you have taken also tests for HIV-2 antibodies as well as for HIV-1.

Further, for you to even bring up PREP is silly, it would be on no benefit at this time, even if you had been at risk which you are not.

Finally, as Dr. Handsfield has already said, searching the internet is a mistake and will more likely mislead you than help.  It is time for you to put your fears behind you and move on.  If you cannot, you do not need to post further, you need to seek the help of a mental health professional to assist you in addressing your fears.  EWH

Believe your test results.  At weeks, antibody tests would detect over 90% of recent infections, including those caused by HIV 2. 

Your wife does not need PREP.  You need to move on.

I cannot comment on the other case you cite except to point out that the situation you describe in most likely not relevant to you. EWH