What are you missing out on because of your preconceived notions of how things will play out? If you allow your doubts and fears that history will repeat itself to clog your head you won’t take full advantage of whats been presented to you. And as a result, history will likely repeat itself. Focus on the NEW aspect of new opportunities or relationships. Don’t hold yourself back, physically and metaphorically, because you want to save yourself from what you perceive as likely trouble. Give it a chance.