For all those bareback curious, here are the numbers and some math. HIV+ person undetectable has viral load less than 20 copies. Recently infected, during the 3 months seronegative window (when old test wouldn't pick up the infection), can have viral load up to 1000000 copies. So the guy can be honest that his last test was negative, but if he is regularly barebacks around, chances are he has contracted it and then you are at 50000 more risk having sex with him than with someone POZ and undetectable. Thats a pretty big number, probably one such encounter is as risky as a whole life of fucking with someone POZ.
The moral of that is? Use the condom! If you don't use the condom your odds to stay neg are better with a POZ guy who knows and manages his condition, than with a NEG guy who doesn't really know his exact status.
