They expect nothing less after divorce.

字面意思是：他们在离婚后期望没有丝毫减少. 但是具体期望的对象是什么要根据上下文来解释.
比如有句类似的话是“Another big change is the greater role played by today's dads in the raising of their kids. Fathers who share in the parenting during marriage expect nothing less after divorce. ”这里的“期望”就是对自己抚养子女的责任的期望,整个话的意思是“另一个大的变化是今天的父亲在养育孩子的过程中发挥了更大的作用.在婚姻中共同抚养孩子的父亲在离婚后也不期望减少（自己抚养孩子的义务）.