I don't totally agree with Christine. Sometimes S is the best thing....especially since you have kids. You will be in contact with W a bunch dealing with kids stuff. Sometimes staying in the same house will just continue to create animosity...both you and W towards each other.
I know there is OM involved in your sitch...so everything you do wrong while living together with W gives her fuel....even if it's the way you eat pretzels. It doesn't matter she is just looking for ways to convince herself that she is making the right decision.
If you S you can show her and the kids unconditional love and also have that space that you both probably need.
Just my opinion....every sitch is different and there is no right or wrong answer. If it was easy none of us would be here.