I will answer your safety concerns in the context of medical health.
It is medically safe to marry someone with Hepatitis B if you take the very safe(medically) Hepatitis B vaccine to immunize yourself against HBV. You can have children and do protect them with the now univerisal HBV vaccine at birth. As for your partner, Hepatitis B is a chronic illness, so he will require regular checkups and receive treatment when it is necessary. The treatment will not cure (at the moment) but it should make him live normally with a normal lifespan.
Having said all that, marriages are made in heaven, sooner or later you will come down to earth and make it work. Heaven forbids, divorces are worst than hell.