I do not want to cheapen betrayal by saying we become better by going through it--although that should be the goal. Betrayal belongs at the bottom of hell. It damages people. You do not emerge out of betrayal unscathed. Particularly people become vengeful, they take it on other people and things spiral downwards. An alternative to this, however hard, is to grow oneself, to choose self-transformation over resentment and vengeance however justified it might seem.