if/when it comes to the crunch idiom
要是到了紧要关头;等到了关键时刻;需要作出决定时
if/when a situation becomes extremely serious and a decision must be made
If it comes to the crunch and you and your husband do split up, you can always stay with us. 如果到最后关头，你和你丈夫非得离婚，你总还可以和我们住在一起。