Second, Not all couples require that both members be involved with all financial transactions. In fact, many relationships work just fine with one person making the financial decisions.
Fifth, people who suggest that there is more going on than what has been presented and actually are suggesting divorce are projecting and giving the OP very bad advice.
Most couples married long enough to be celebrating their 10th wedding anniversary have this all figured out already, and aren't shocked, surprised, and dismayed by the actions of the spouse, who is not explaining where the money went well enough, and is allowed her to be and stay confused.
People here base their thoughts and feelings on what they know of human nature, and their own pasts. This is invaluable to many people. No one here FORCES others to do anything; they simply help to open up minds to see that some things aren't right or OK. People in abusive relationships often *do not know* that what is happening to them is abuse. They have been told that THEY are in the wrong so many times that they question themselves, and need someone else to step in and tell the truth.
Maybe this guy is just so upset he can't talk straight. Maybe this stuff has never happened before. Or maybe this is a series of problems that has happened since they met, and this will be the straw that broke the camel's back, once she realizes that it's not acceptable.
How about the OP and her husband simply work on having more open communications? Perhaps the husband hasn't previously discussed this issue because he knew that the discussion wouldn't be welcomed? I have no knowledge as to whether that's true, but it certainly is possible.
Go on the trip anyway? Even though the money for the trip is no longer available? I just don't see this as a responsible financial decision, let alone the damage that such a decision would do to the relationship.
After 10 years of marriage a problem caused by a one-time communication breakdown would not cause such dismay. The husband wouldn't be telling her she's selfish, she wouldn't be so confused because he would open up the financial info for her to see, and would explain it all.
DVC is paid, I assume their way of getting there is paid. If she goes alone, that's a whole lot less money for food being paid. So what money IS there left, really?