All very good questions. I have struggled with it all, too.
As for the "what if the WAS was right?"... I don't think there's a right or wrong. It's about the willingness of both partners to try to get back what drew them to each other in teh first place, and build a new M from that. Both partners need to want this.
As the LBS, you can't control if your WAS wants to work on the M or not. What you can control is keeping a sense of balance and peace within. That is where the working on yourself thing comes into play. I also think that by giving the WAS some space to think through what they wants helps, too.
IN your case, it sounds like your H is living at home with you, but there's not much there. I've been there, too. And this is when all the above stuff gets really hard.
As for the thing with the kids, I think having kids is an additional motivator for working on a M. I don't think it's a reason to stay M if it's not a good M.
In my case, physical separation was absolutely necessary for my H and I to get back on track. My H had an A with OW and tried to come back many times but didn't "feel" waht he was supposed to for me. So, by being separated, he worked through all that -- and we worked through it. It was very hard. It was filled with ups and downs. But now he is home and has been since June.
I don't agree that a separation will likely lead to D. It can go either way.
You need to do what makes you the healthiest.
Married 9 years Kids 5 and 6 Bomb 2006 H back and forth for a year M now back on track