It's not a stupid question to ask, "When did I get the HPV infection?" The problem is that it's impossible to answer unless you've only had one sexual partner.
Since HPV has no symptoms, over 80% of people have it, and nobody knows it until the Pap smear with HPV testing shows it.
And that's why it's dangerous.
Some women will stop going to the gynecologist once they're in a monogamous, long-term relationship. If the couple doesn't have any other sexually-transmitted diseases, that would usually be okay, but...
Cervical cancer takes years to develop after HPV infection.
Let's say a woman becomes sexually active at 20 years old. She can't take the pill because it makes her gain weight, so her boyfriends use condoms. She doesn't go to the gynecologist every year because she doesn't think she needs to since they use condoms and she isn't promiscuous. She only has 2 long-term boyfriends in her 20s. She meets "the one" and gets married when she's 32 years old.
She gets pregnant when she's 33, and goes to the obstetrician, who does a Pap smear, which is routine in pregnant women. The Pap smear is abnormal, and a colposcopy confirms moderate dysplasia. They wait until after delivery to do a LEEP, and that's when early stage cervical cancer is found.
She probably didn't get HPV from her husband. She most likely got it in her 20s and her body didn't take care of it, so it slowly developed into cervical cancer. Because she didn't go to the gynecologist regularly, it wasn't caught when it was just dysplasia.
We know that 50% of cervical cancer occurs in women who have never had a Pap smear. Catching dysplasia early and removing the tissue before it becomes cancer is so important!
Also, remember that HPV can be transmitted even when the man wears a condom.
Cervical cancer takes years to develop, and if your immune system doesn't tackle HPV on its own, you are at risk for cancer even if you and your current partner are monogamous.