I absolutely agree that your relationship and interaction with your H will be confusing to your kids, regardless of what those interactions might be. If you want nothing to do with him, they will wonder why. Both of you will be suspect in the minds of the kids and then... they will also possibly suspect themselves as being the reason. In just the same way that they will have hopes if the two of you are even civil with each other, never mind going on a trip together and staying in the same room.
Going on this outing in the first place will send mixed messages to the kids, in the same way as not going along, even though there is a ticket for you. In the same way as travelling together, yet staying in separate rooms or staying in separate buildings.
AD. You need to decide what YOU want, here. What ever you do... or do not... will have positive and negative consequences...
Friends can share a room... or friends can travel separately... You have accepted the ticket from your H and the ride. Why could you not accept the room?
Of course, I am only speaking to your sitch. I would go with a friend. I would travel together. And I would share a room with them. Even if your kids thought that maybe the two of you were to get back together, at the very least they would see that the two of you can get along.
