HPV is so easily transmitted that at this point, you and your partner have already swapped strains of HPV. With HPV, sex is sex. Heck, it doesn't even have to be sexual intercourse to transmit the virus. It is transmitted by any genital skin contact with any other genital skin contact.
So, I'd say it if the two of you have had oral sex before then you aren't likely to spread or protect against the spread of any other strains of HPV (unless either of you is not monogamous).
My Dr. explained to me that there are various strains of HPV. It is most likely that you and your partner have already transmitted strains of HPV. Your risk of being exposed to a new strain would be highest if you were to become intimate with a new partner. If you know approximately how long you have had HPV, it will be relatively simple to determine whether or not you and your partner have (already) participated in oral sex and sexual intercourse while you were infected with HPV. My husband transmitted HPV to me; we have a healthy, normal sex life. As we are monogamous, we do participate in oral sex and sexual intercourse as we know that we have the same strain.