Thisby

I would say that if you know you husband has been unfaithful (which is how you phrased it, as a statement not a hypothetical) then it is more logical to assume it's from that, rather than a reappearance after a long period of dormancy since HPV usually manifests itself sooner rather than later.

But if you don't know, don't assume he has been unfaithful because either scenario is possible.