5LL's is great, required reading, but trying to apply it now will come across as pursuing. Read it, internalize it, but measure how you apply it at this point.
WRT moving out, in my state I spoke to a lawyer who strongly cautioned against it. He said that W's L can spin that into an abandonment claim and you will have issues if things go to court. As others have said, let W move out first. My sister got divorced and her H stayed in the house until the bitter end. He used that as leverage during the divorce proceedings -- i.e. "if you want me out earlier, then you need to compromise on X and Y."
Finally, it's obvious you're having a hard time giving space -- everyone has that problem. One thing I read that was helpful is that you have 2 options:
1) Hope the situation will get better 2) Assume things will never get better and act on that basis
It said that #1 is based on "hope" -- when you have hope, you have expectations. When those expectations are not met, it will lead you to be frustrated and/or get angry. That frustration and anger will cause you to react and act in a less than ideal way. The expectations are constantly refreshed when you're holding onto that hope. i.e. "I asked W to text me if she will be staying away over night". You have an expectation (and a hope) that she will text you. When she does not text you, you get frustrated and angry. The unfortunate thing is that this path can lead to perpetual pain, as you cling to the hope that things will improve, you are disappointed every day that they do not.
It said that the power of going with #2 is that you're able to escape from your expectations and can start to detach. If you assume that W will never treat you any better than she is treating you now, then you won't have expectations for anything better that W then won't fulfill. It said to expect this path to be very painful -- you will mourn your lost expectations. On the other hand, it's a journey with an end. You go through intense pain and come out the other side detached and ready to move on with a more realistic view of your situation.
I know this sounds very depressing, like hope is a bad thing, but it also seems to be pragmatic advice in terms of getting to a place where you can *truly* give space.
It is your expectations that are your worst enemy right now -- expectations that you have the power to turn things around quickly, expectations that doing something nice for W should result in W being nice to you, expectations that showing progress with 180's should cause W to change her mind, expectations that having a better relationship with SIL should influence W to want to work on the M, etc etc etc.
While W is a WAW, those expectations are perpetually unmet and it creates day to day pain and angst for you. If you can drop those expectations, you'll be in a much better place to weather the storm. Assume that W will do nothing to work on or repair the relationship. Assume that W will not be influenced by your actions, your family, or her family. Operate from that assumption and you may find peace sooner than you would otherwise.
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015