hbv is cronic at birth only or very early childhood, in some asian countries like china and philippines it is so spread that most population got the virus and cleared it
just check if you are cronic too or cleared, if not get vaccine and just forget about hbv
get your BF to check liver damage by fibroscan every 6-12months and start tenofovir in case of fibroscan more than 7kpa
stef2011 is correct, check whether you are infected with HBV. If you are not infected, immediately get the vaccine and not worry about it. My wife had HBV vaccine and i was very relieved.
you should also introduce your BF to this community and help educate him about HBV, tests, treatment options, etc
hope this will help.
You CANT get HBV thru kissing unless may mga sugat kayo sa bibig na nag dudugo, but you cant get it thru saliva.