Vampires in the House

We are all aware of vampires in movies and literature. Nothing like good ole Count Dracula, the Twilight series, or the short lived tv drama, Kindred, The Embraced to make our hearts race.
Those are not the critters I want to talk about today.
The ones mentioned above are easily recognizable (think fangs!), and easily dealt with according to the rules of folklore and tradition. 
What I am focusing on today are "Psychic Vampires." Put away the garlic. It won't help. 
These vampires are subtler, look normal, and feed off your energy just as surely and relentlessly as the fantasy ones do off blood.
These creatures can be male or female, can be charming and physically attractive, and may not even know they are psychic vampires. 
They are usually chronic complainers, refuse to take responsibility for their behavior or decisions, and need to be rescued a lot; they prefer being dependent as this allows them to blame someone else if everything does not go their way. 
They seem to firmly believe that they have more troubles than anyone else and will ask how can they possibly cope without your help and support?
They are like whiney children in adult bodies, with endless lists of excuses for everything.
A good friend of mine called her former spouse "an bottomless pit of wants and needs".
Life with these people is perpetual drama and manipulation, which can leave the rescuer drained, sapped, withered, and as lifeless in some ways as one of the fantasy vampire's victims. 
It is never ending confrontation, confusion, and conflict with the psychic vampire often honestly unaware of the havoc they wreak in others' lives and intensely resentful of any boundaries set. How dare you expect them to grow up!
You should just apologize for even suggesting such a thing...in their view. Indeed, life with such a person can mean daily or even hourly appeasement. 
What can you do to avoid these people or to deal with one of them, if you recognize them in the description here?
If you are in a committed relationship, especially of long duration, it is more difficult, of course. Professional counseling may be helpful, provided you can convince them to agree and to actually go. 
Setting definte boundaries and following through, in spite of resistance, can sometimes be helpful also. Assertiveness with such a person is not easy, but absolutely necessary.
The bottom line is how is their behavior impacting you and the family, and how willing and ready are you for that to change? That is something only you can decide. There are different degrees and manifestations of this behavior, and different levels of people's ability to tolerate it.
Unfortunately, for some of us, distance is the only option for survival. They will wail that they are being abandoned, but continuing to "help" them is not helping so much as enabling. 
Just as you would not hand liquor to an alcoholic or drugs to an addict, so some of us cannot continue to let this person feed off our energy and drain us. It is unhealthy for both parties and goes far past co-dependent. 
Granted, some well meaning and helping people seem to thrive on the chaos and conflict inherent in life with a vampire, but sooner or later, these relationships take their toll on even the hardiest rescuers and caretakers with the best of intentions.
This is in no way an example of professional or expert advice. It is just something I wanted to mention and call attention to after having experienced some of these energy vampires myself. 
There is extensive information out there and help is available if you or someone you know is dealing with this.