Hi C.. Non-sexual transmission of human papilloma virus (HPV) is controversial, but definitely possible. One small study even showed that exposure may occur via shaking hands with someone who has genital warts! [Sexually Transmitted Infections 1999 Oct;75(5):317-9].
It is documented that infected mothers can pass HPV to their offspring in the course of a vaginal delivery [Rev Med Virol 1999 Jan-Mar;9(1):15-21], but this would be detected in the linings of the nose and mouth.
Your colposcopy results are not infallible. You should ask your doctor to do a specific HPV test on you. Even if that is positive, as long as you and your husband are confident that your relationship has been mutually monogamous, it doesn't help matters to try to figure out how you may have been infected. What matters most is to discuss a plan with your doctor about how you will monitor your pap smears going forward.