OP, I just read alot of this thread and I hope things are going okay for you. I hope the trip works out...I really think this is something you (and especially) the kids need. You need to show your kids AND your DH that you're a strong woman(then go hide in the closet and cry if need be).
I too, have BTDT..to a degree. DH and I have been married for 13 years. We've been thru hades and high water together and have made it thru. After the birth of our 3rd DD, things began to go downhill. He told me several times he felt unappreciated, yet I felt the same way. Neither of us got it and, on the advice of a friend, DH began to pull farther away from me to "show me" that he "didn't need me". What bad advice. I had made a new group of friends on the computer and alot of my attention was going places it shouldn't have. To make a long and painful story short, DH got a rude awakening and since then our marriage has never been better. We "found" each other again and I have my best friend back, better than before.
What I'm trying to say is, this may be something that needed to happen. Whether it be for you, or for your marriage. Your DH may be confused and just needs to sort some things out. I certainly don't agree with the way he did it, esp. where the kids are concerned, but none of us are perfect, and there are times when all we can do is our best AT THE TIME.
You will make it thru this, and will be stronger for it, regardless of the outcome. I promise.

and I'll keep you in my prayers!