According to the Worst-Case Scenario Survival Handbook: Paranormal Edition:
HOW TO BREAK UP WITH A VAMPIRE
Pace the floors of the castle. Stare up at the cold light of the moon. Sigh, moan, and curse the day you ever met him.
2. Weigh the pros and cons.
Confirm that you have made the right decision by making a list of plusses and minuses to continuing the relationship. List as many cons (e.g., committed to evil) as possible. For any pros (e.g., promise of eternal life), are there downsides (e.g., eternal boredom)?
Don’t break up with the vampire on Valentine’s Day, his birthday or rebirth day, or when he hasn’t feasted for several days.
It can be hard to maintain your nerve while staring into the literally mesmerizing eyes of a vampire. Close your eyes, or look out the window, while telling him how you feel.
As with any breakup, your goal is to tell the truth without being overly informative. Say your piece and then stop speaking.
6. Don’t make it about the vampirism.
Find other reasons to explain the breakup, such as his personal habits or friends, rather than the fact that he is a heartless, shape-shifting destroyer of men.
The vampire may protest, saying that he can change. Remind yourself that he’s been alive for many centuries and genuine change is unlikely.
8. Keep it about the two of you.
If you have fallen for someone else, do not mention it, vampires are notorious seekers of vengeance.
9. Skip the goodbye kiss.
HOW TO GET OVER A VAMPIRE
A good rule of thumb is that getting over someone takes half the length of time as the relationship itself. If you’ve been dating the vampire for countless millennia, count on a similarly epic grieving period.
* Remove evidence of the vampire from your life.
Don’t listen to his favorite songs; throw away his old capes; scrub the bloodstains from around the house.
* Focus on the bad times.
When you think about the vampire, remember the tedious nights spent traipsing through graveyards, the gross spectacle of his feasting on human flesh, or how cold and distant he could be.
Avoid dating other vampires, since you will be more likely to run into your ex at social events.  Consider dating in another species or professional circle, such as a werewolf or a warlock.
What else would you like to learn?