Sometimes when you know the relationship has come to the end of it's path it's best to just let go rather than trying desperately to hold on to something that isn't there anymore. I'm a little unclear why you are still going on a trip together though seeing that you know the relationship is over. Isn't it going to be more painful for both of you to go on this trip?
All relationships are beneficial, even if they don't end up being long term. You have learned about yourself and what you require in a mate. If you are looking for someone who will be more involved with you in day to day life stuff that includes your husband then that is something you can speak to people you are potentially going to be involved with in the future.
I know that none of this helps with the pain that you are feeling at the moment. The pain will lessen in time and it's my belief that everything happens for a reason and this relationship has gotten you ready for something else that is coming your way.
Everything will be ok in the end. If it's not ok it's not the end.