((titanium))
The feelings of confusion and hurt, even hate, last a while. Double betrayal is especially hard to process, because the betrayer uses their inside knowledge of you, to hurt you. That makes it especially personal and complicated.
Over the years, I have found that the betrayal at the hands of my so called friends, is harder to deal with. Many of us wouldn't even consider doing this kind of thing to a complete stranger. I wouldn't even do this to someone I disliked.
I can not fathom that your best friend or your WH would gamble with your life, while you were fighting to save it. In my eyes, that takes cold hearted to a new level.
She makes a much better enemy than she does a friend.
One way you can build the strength to reject her, is took at her for who she is, no what you believed she was. But now she has removed her mask and shown you the real her. It's going to take some time to mourn the loss of the friendship you believed you had.
This was no friend. She was a wolf in sheep's clothing. She is toxic and would rather keep you sick. Adding this kind of stress into your life, after your sickness, is the lowest of low.
Try think of her as a sickness, that needs to be removed from your life. She's been feeding off of you, and taking from you, and the only way to end that, is to cut her off from your heart, and your mind.
Keep NC with her, even in thought. You could learn some techniques to do this in IC.
I also recommend limiting contact with your WH as much as possible. His access to you and discussions about anything other than the children and finances, continue to hurt you, and provide a way for you to mentally attach to thoughts of your fakefriend.
I don't know if you are posting in the forum for divorce/separation, but since you are living separately, you might draw some strength from their experiences. I think those folks might be able to help you through the challenges of necessary communication with your WH.
You deserve to be healthy, happy and surrounded by people who love you.
((titanium))