1 in millions chance or longer. Whilst your updating your status for partners though, it is a great set of negative results to show!
This is pretty low risk of anything. But it sounds like you need to test to put your mind at ease. At two weeks have a throat swab for gon and chlam. At 12 weeks test for HIV, Hep B/C and syphilis.
Overall though with zero symptoms, testing is not recommended for such a low risk event.