Anyhow, communication between couples is the most important thing, maybe case-dough is just the outcome of non-communication and distrust.
无论怎样，夫妻间的沟通是最重要的，私房钱也许就是缺少沟通彼此不信任的产物。
2
Case-dough means that someone has some money secretly and would like to keep it permanently secret, especially he doesn't want his spouse to know it, because he has some purpose.
私房钱指某人偷偷地将钱留起来并希望永远没人知道，尤其不希望他的伴侣知道，因为他是有目的的。
3
Many other situations which cann't be finished here, in one word, as long as the case-dough is reasonable and being used properly, I would support that.