Yes it is possible not only for HIV but other STDs that are easier to contract.
so u think its possible then for me to contract hiv after 1 exposure to unknown status, then one sexual encounter with my parter to infect her and my baby also?
Yes, the chances are considered to be low in acquiring the virus over a single episode of heterosexual exposure. However, if you really did have an unprotected exposure, you have certainly put yourself in to some amount of risk.
From there, if you really acquired the virus at the first place and had unprotected sex with your other partner, you have also put your pregnant partner and apparantely the newborn baby in to risk.
Would you say its likely this could happen then Teak?
Test three months post exposure for a conclusive test result.