You never had an exposure.
Your question is hard to follow,however odds won't tell you your status,only testing will and if you had a risk you need to test it's that simple.
foer example if a sexworker sex with a positive man and his semnen was in his body and a little time later sex uncover with a healy man is this little amount( 1 in 1000) increase?
The bottom line is that a risk is a risk and you should always use protection no matter what.
i say what happened that only one time uncovered sex for huge amount of people has infected them when there is very little probability of infecting? for example being blood or another?
They are the odds if a man has unprotected penetrative vaginal sex with an HIV infected woman.If she was on medication it might a 1 in 2000 chance.