My occults are about as likely to go steady with a human as they are with their own kind. Both physiology and psychology are close enough to make such unions possible, yet different enough to make them interesting for me, especially if their cultures do not officially support such couples. It's not just those sims' stories, styling sims of mixed human/occult heritage is also great fun for me.
(At the moment the "occults" I play the most are androids, admittedly, but I also have a few real ones mixed in.)
Vampires are the exception, since I treat vampirism as the result of a curse by (the) god(s) in most of my saves. Living in a partnership with a vampire leaves its mark on the soul; either by corrupting the human (more likely) or by redeeming the vampire (can happen). In the first case the formerly mixed couple is now vampire/vampire, in the latter it becomes human/human. The most recent vampire/human union I had was two years ago.
