If the
porn wasn't really that big a deal to you then you haven't got anything to
worry about. Anyway, you can always get
more if you want to later. It's nice of you to
consider that your fiance could have been
unhappy with you having porn, but some people will say you should have asked her what she
thought. Don't
listen to them. Using porn is just another aspect of a person's
sex life and as such it can be a very
private thing.
If you think the feds might be after your computer, though, be aware that just deleting something doesn't mean it's not detectable any more. Files can sometimes still be recovered from a hard drive after the area of the disk that they occupied has been overwritten many times.