We all have a past and we can't change anything that we have done. I would be concerned with a potential partner's HIV and other STD status regardless of whether or not any of their past sexual encounters were caught on tape, as we all have a sexual past. It is difficult for anyone to discuss previous sexual liaisons with their partners, and I applaud anyone who is forthcoming enough to share something as potentially explosive as having starred in a "few amateur porn videos" - which, IMHO, is a far cry from being a porn star. We claim that we want honesty from our partners, but the phrase comes to mind ... "The truth? You can't handle the truth!"
In the final analysis, if the relationship is strong and there are no other major issues, I don't see a problem with skeletons that are no longer in the closet. It is the unknown that is far more frightening to me.