How do you handle the betrayal of a friend?

Changing ur way of thinking on how people behave... I've cut friends out because of their betrayal. I've been betrayed by my sister & brother, I've been trying to put myself in the frame of mind that I can't trust them so be careful of what I say to them. Cutting my siblings isn't really an option for me... currently going through a divorce & my ex husband has blamed everything on me & not taking responsibility of his own acti& is being a shit head about the financial stuff, I find that as a betrayal as he isn't being reasonable... there is nothing I can do... but again I need to change my frame of mind of feeling shit about it & look for the positives. If these people who have done me wrong... its their problem, they aren't gud people, if they were gud, they wudnt act the way they did... no one has the right to nake u feel less than u are or treat u badly...