The kids and I are definitely going. If H decides to stay in the marriage, he will come too. Otherwise, we will tell the kids about the issue a week before we leave, and he will stay behind.
Tickets were purchased before BD, so H's ticket is a sunk cost.
The only exception I can see is if H and I develop the ability to go several weeks without an R talk. In that case, he might come even while he is still undecided. (We are still sleeping in the same room at home.)
Me: 44 H: 44 Kids: 20, 16, 16, and 10 Together/Married: 22 years H announced he was emotionally detached and considering D: 4/4/16 H announced he is going to try to stay and reconnect: 5/1/16