from what i have read so far, if your husband has had hep b and you have to yet to contract it then u are either already immune to it or if u dont know then you should go get the series of hep b shots..
The fact that you are testing negative is great! I agree with Naiphan that you should get the immunizations at this point to ensure you don't get it!!
One warning, if you get the immunizations, make sure the Doctors follows up afterwards to determine if they worked. I have Hep B and the kicker for me was that I had been previously immunized but I was one of the 10% or so where the immunizations don't work and they never did follow-up testing to find out. Subsequesntly I get exposed to the virus, thinking I am protected, and am now suffering a very nasty surprise!