Sounds like the xh is having some money problems. He apparently isn't doing any financial planning and is spending the money as quickly as he gets it. If money is tight, most normal people would cancel the vacation and stay at home. That's his problem if he doesn't have any money and I would certainly not cough up any money to help him out.
Your son sounds more responsible than your xh or his honey dew. If your son is working and has financial responsibilities of his own, then he has every right to say no to the trip and your xh needs to leave it alone. As for your other child...your xh will need to come up w/some money for the vacation since he's the one that is making this happen.
I also think he's nuts to even think about spending any unnecessary funds at this time if there is going to be some issues at work. But again, rational, mature people would not be out here spending left and right.
I wouldn't get into any more discussions w/him about the finances except to keep my eye on the support money. If he doesn't come thru, you may have to take him back to court. In many ways he's having to face the consequences of his actions and I guess honey dew will need to get a job or a couple of jobs to help sugar daddy out a bit.
Keep moving forward and try to engage w/him again about his money issues. Keep the focus on you and your children.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
