Resolving relationships will surface unpleasant feelings on both sides. Isn't it better to forget and let go?

Forgetting is an easy option which most of us practice. However, forgetting/ ignoring only suppresses the emotions deeper into us. It does not help us in releasing those emotions. 
Our mind often tricks us into believing that we are not carrying anything against the person. There is a simple test to check it. If the memory of the person, does not invoke a feeling like blame, hurt, resentment, anger, etc in your heart, it means that the relationship is not strained. 

However, if you feel these feelings for the other person, it means that there is a need to release these feelings. You can refer to the do's and don'ts while expressing. 

Also remember, the reaction from the other person is not in our hands. We can express ourselves, let go of the weight and set ourselves free.