Hi mmadison --

Here's Gail -- as Brian said, I am coming out of a similar experience though my husband's cancer was tonsil/base-of-tongue and also had spread to his lymph nodes. He was HPV-16+ and we found out because he was treated at Hopkins and they test everyone now -- finding very high percentage of their new HNC patients are HPV+ (but not all).

Dr. Maura Gillison, who is heading up much of the HPV/HNC work at Hopkins told us that my husband may have contracted the virus 15 or evn 20 years before developing his cancer, that it often takes years for the infection to result in cancer in those people whose immune systems did not shed this ubiquitous virus. (About 70-80% of us get infected with it at some time in our lives, I have read).

I agree with Brian that you cannot distract yourself with guilt or blame because there is no way of knowing the answer -- even if your husband does turn out to have an HPV-16+ cancer. And as far as that goes, very few lateral (mobile) tongue cancers appear to be HPV-associated according to some studies (e.g. Int J Cancer. 2004 Dec 20;112(6):1015-9.
"Human papillomavirus is more common in base of tongue than in mobile tongue cancer and is a favorable prognostic factor in base of tongue cancer patients." Dahlgren L at al.) so it may be a moot point.

If you wish, you can get a tissue sample tested for HPV at Hopkins, though as Brian says it will not change the treatment protocol. If it will give you peace of mind, however....

http://pathology.jhu.edu/labservices/hpv.cfm

Be strong, your husband wil need you a lot in the coming months, but this disease can be beaten -- as you will learn from the many great folks on this forum...

Gail