http://www.cdc.gov/std/hpv/stdfact-hpv.htm
Show your partner this link. Educate her. If she has been sexually active, she probably has been exposed to it. Safe sex isn't perfect but offer to always wear a condom. Most people don't say anything esp if their partner has been sexually active (4 or more partners in their entire life).
Wear a condom and don't say anything. If she has been sexually active (4 or more partners in her entire life), then she has been exposed to it too. Most doctors tell their patients not to say anything because 8 out of 10 sexually active adults have it. Although half don't know due to no warts, the lack of a HPV status test for men, the high risk strains that produce no warts, etc. If you feel that you must tell her, then educate her at the same time. Go to http://www.cdc.gov/std/hpv/stdfact-hpv.htm and print it out for her in case she needs more info. There is no such thing as safe sex and if she has been mis-led into thinking that the condom protected her with past partners, this fact sheet will educate her since condoms provide maybe 50% protection.