That feeling of being cheated when the person you have been fighting for is talking to the person you are fighting with. Talking behind someone’s back to enemy is nothing less than slander. And in the process of saving their own relations and skin, they break up another.
Do they not realise all the trouble someone underwent only for them. And what was their contribution? Backstabbing? Do they not realise the same can happen to them too and they could feel equally alienated?
Slander and relation can never go together.