Your sympathy for your W is the same place my head is at. And for me it is causing serious confusion, bouncing between anger and sympathy rapidly.
During mediation my W was being selfish. It was painful. My IC said greed is driven by fear. Yep, I can see that now, but had trouble with it at the time. Looking back at the final outcome a week later, it looked a lot better to me than the day of. Not fair, but better. Fear was controlling me also, with some greed even.
Many people have told me "it's just stuff." Took a long time for that to sink in too, still frustrating that I worked so hard to give up so much, but I'm getting there.
I don't think "fantasy" is the right word for your W's state. That term is used a lot on here. I think an "escape" might be a better word. It's not necessarily better, in fact it likely isn't. Is that the picture we paint of where they are when we are angry, that it is a fantasy? While actually they are stewing in their own misery scrambling trying to find that piece of themselves that they "think" is going to make them happy?
Destroying lives, including the children's.... Yep, I hear you. So selfish! Wait, are we feeling sorry for her or angry at her at the moment we think she is being selfish? Obviously anger.
I've heard plenty of comments from my kids. In my pain I doubt I responded perfectly. In fact I screwed up fairly bad a couple times. Then had to try to repair the damage I caused. The latest tear-jerker, a couple weeks ago, we went out on the deck to look at the stars. I told the kids to have a wish ready in case they saw a falling star. We didn't see any, I was disappointed. So I asked S11 and D9 what their wishes were, they both said they wished for us to be back together. This is after we've been apart for almost 6 months!
I will guess it will be a long time before they feel anything different. Will probably depend on if one of the parents screws up often enough to cause resentment. Once that happens, the kids will likely think the D was for the best, and the better parent will be told you would be a fool to take the other back. I've seen it before a few times.