Info Re garrding Hepatitis B?

hi my ex girl friend has been tested positive for hepatitis's B and i have tested negative after 6months after the exposure and still i am worried about that do i get infected with it i have consulted doctor he is telling the incubation period is max 4 months in some sites its telling 6 months though i have crossed the 6 months incubation period i am still scared do i need to take a test after 7 months and so on or should i stop it please help me with your suggestions