I think it depends if you can afford it, or if it's going to be adding debt to the family. Now is NOT a good time to be adding debt in this economy, needless to say.
If you can afford it, and you can take the kids without her, then I think you should go (although I would have preferred that you hadn't said "no" to begin with). If you CAN'T afford it, then you should cancel it and do something less expensive with the kids -- just you and them.
