Has anyone had an abnormal pap test, no std's?

After I began having sex, the past two years I've had pap tests come back abnormal. Checked for STD's, because my has had other partners before me, and they came back fine. I've only had one partner. My bf said it comes back abnormal because we have sex so much. I usually dismiss him and think that is silly. But I wonder if that has any truth to it since I can't figure out what else it may be. Doctor just said to continue with my annual tests. Just so confused.