Er, I don't really know any pornstars. I don't think a relationship based entierly on physical attraction (even if mutual) would last. That's not to say I wouldn't be willing to try of course.
That aside, I'm not sure I could handle it. Unless they quit or just model, I think I'd be rather unhappy. No hardcore, that'd be too much for me. Maybe with other women, it's a bit different since it wouldn't be the same sense of being replaced. It's a bit hard to say since I've never been in that position.