It truly isn't complicated. The more you support her the worse it will be in the long run. It's called enabling.
It's not your job to resolve your WW issues, mental or physical. And if she does harm herself then that's not something you as an amateur can prevent. She will need a plethora of professionals.
Your WW isn't in MLC, she is compulsive and possibly mentally ill and not being treated. Her parents can step in.
You are not to 'blame' for this, or for her moving.
The most loving thing you can do is let it happen, the sooner the better. And protect your family. Do this for your family and for WW too. Hold that which is precious safe. You can do this.
There is no guilt in it. You are doing what is right and leaving WW to the correct devices, it doesn't help if you go under too.
I like Loves post very much indeed. We are saying the same thing in different ways.
V
Freedom is just another word for nothing left to loose. V 64, WAW