First of all, hugs to you. You are certainly dealing with a lot these days!
You are doing so well with the kids. I am very impressed with the prayers (even for OW? Wow-- that is just great that you can do that) and the talks that you are having. I see no way of handling this better.
My question to you is this: Who made the suggestion of counseling that your H agreed to?
Now another one: If he did go, what do you hope for it to accomplish?
I guess I want to see where you are with this before I offer up my opinion. I do have to say that I like the sound of the psychologist that your kids are seeing. I mean, recommending DB must mean pro-marriage...and, more importantly, someone who won't just flippantly tell him that the kids will be fine. "Kids are resilient." Man, I HATE that saying!!!
As for the house.. are you SURE you won't be able to stay in it? Though, it does sound as if a smaller one might be better for you anyway. (less cleaning! :)) If you know that it has to be sold, well, I always recommend being in control when you can, so that would mean contacting the realtor. You don't have to sign anything right now, but it would be helpful for you to have someone come out and give you an idea of what it could sell for, as well as to tell you the things that need to be done to get it ready to sell. As I recall, your H isn't really keeping up with things around there. All of this information is good to have, and again, it doesn't mean that you have to put it on the market right away.
Again, I am really sorry you are dealing with all of this.