Oral sex is not 100% safe. It is more safe than genital sex but it is not and never has been completely safe from transmission of HPV. If you are under 26, get the vaccine. If not, then reduce the number of partners in your life and play safe. Condoms provide 50% protection but its better than none. The absence of warts does not mean you or your BF does not have HPV. Women can get tested, man cannot.
Read up on this for more insight. Educate your BF too.
http://www.cdc.gov/std/hpv/stdfact-hpv.htm