Soulmates

A vampire inlove with an alien, he doesn't know she is not a vampire but after century of dating they always end up breaking up, he believes they are destined to be together but she hides a dark secret from him she is a spy alien sent to learn the ways of the human race before erasing and replacing them with their species (Marian from mars) . After Every century she goes back to her home planet to report her findings on earth.