Narcissists don't like boundaries - they see them as an attack on them. How dare you tell her she can't arrive whenever she likes? Or stay as long as she wants? Or indeed, how dare you put any limits on her at all?
Trying to put boundaries in place can set off narcissistic rage or tears or 'victim mode', or whatever her method of choice is. And that can limit your actions, make you give in.
This video will give you the mental and emotional strength to set, and then enforce, boundaries regardless of her reaction.
How long would it take you in counselling to get to this point? How much would that cost you? Hundreds, no doubt. This MP4, which you can use as many times as you need, is only $17.00.
There's also a no-quibble 60 day money-back guarantee so you can try it out completely risk-free before deciding if you'll keep it.