I get the consent argument, but a lot of porn is about fantasy

Is it OK to think of some hot actress while you're having sex with your wife?

I guess you could take care of the consent thing by getting someone that looks remarkably like the hot actress and then pinning her face into a porn video where the actress from that video says it's OK; but I think we all know that's not going to happen; and it's possibly still libel unless it was explicitly marked as not being the actress

Hot actress! Do you know how to find her on myspace?