What are some good idioms that mean "someone betrayed us"? I can think of the expression "a stab in the back", but I can't think of anything else. I am also looking for a phrasal idiom that can be used like a complete sentence like "He made a face on him". Is there anything like that you can think of?
pull the rug out from under someone
She pulled the rug out from under me.
This means I was expecting things to be a certain way, but suddenly she changed the rules.
throw someone under the bus
His boss threw him under the bus.
This means his boss sacrificed him. For example, their funding was cut, and the boss didn't stand firm and insist that he be kept on the job, but instead fired him and blamed all the problems on him.