I think our spouses can, and many do, work on their issues while still living with us. I know my wife is. Might not be at our speed though, right?
Your W feels guilt yet still wants to see you happy, even please you. Dealing with incredible pain, she's not withholding love... she's likely giving you the best she can right now.
Does she say/do other nice things for you? Maybe you can build on that. You have noticed that she is reconnecting with S. These are the kind of things that make staying tolerable... or even pleasant! It won't always be as difficult as it is now, Cali.
Removing her training wheels may or may not play out like you hope it will.
Move out only if that's what you need for you, not because you believe it will teach W to fix herself.
What compassion and commitment it shows that you've been her friend during the worst crisis of her life. She does notice this, Cali.
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl