Welcome to Healthcare magic!
Since you have protected sex with the sex worker, the risk of transmission is negligible. Moreover you do not know whether she is positive for HIV
You have already done the test and it is negative.
After 'suspected' exposure, tests for HIV is done 3 months and 6 months after exposure. If they are negative, then the person is not infected.
You have done the test nearly 16 months after the exposure and you were negative for HIV.
So it shows you are not infected with HIV from that sex worker.
So do not worry.
You can go ahead with your marriage :-)