It is not easy to overcome it totally. Yet, pondering upon it in an unbiased manner and probably even re-enacting it and rationalizing it as an outsider, the situations appear to be no more than a trivia. In a situation like that it's always a good idea to change shoes. One can visualize how one's action would affect one self. This will help in a better understanding and the idea of forgiveness will take charge easily.
Communications is the best course to settle issues.
Unless we talk we would not know what the other person is thinking. I have found honesty is a very good thing in building a good and loving relationship. In the beginning, honesty could be cruel but in the long run it builds up sound relationship. Being able to trust each other is the best thing in a relationship. No matter how much one hurts the other - it can be forgiven but dishonesty is one thing that appears absolutely unforgivable.