I'm glad you posted your story and I'm sorry you're in this situation. I honestly don't know if it's easier if the WAS is still in the house or not. Pros and cons I guess, but I think as long as your W is there, you have an opportunity that I didn't to really show her you're getting on with your life (GAL) and even though you're not happy with her choices, you're going to be OK. Act 'as if', do those 180's. Since you're the SAH dad, I'm sure you need some time away from home to yourself. Make plans to do the things you used to enjoy and may have given up. Reconnect with old friends. Try something new.
Even though the MC thinks it's over, it doesn't mean it is. What's in your heart? Do you want to keep fighting for your M? If so, pay no mind to the nay-sayers and think positive thoughts and become the guy that only a fool would leave!
Oh, and although my H left us, from what I've read if your wife tries to get you to move out, don't do it. She can leave if she's determined, and you can't control her actions. But if you don't want the S or D, then don't leave if you can help it!