Many people struggle with the concept of forgiveness because it is often connected to forgetting a wrong or to re-establishing a relationship as though a wrong never happened at all. While forgiveness may be partnered with either of those things, neither is an essential element of forgiveness. What is essential to forgiveness is the letting go of the hurt, pain and rage caused by another. When you forgive, you do something that is good for you -- not just mentally or emotionally, but also physically.

The Short Answer Is Yes

You should forgive your friend because it's the right thing to do -- not for her, but for you. While certainly your friend may benefit from you no longer being angry, you receive the real benefits of forgiveness. That gut-clenching wave of emotion you feel when you look at her or hear her laughing down the hall is gone. That heart-squeezing pain you feel when you think of her going behind your back to be all flirty with your boyfriend disappears. Your tension and stress dissipates. Duke University researchers found forgiving promoted better immune system function, according to the "U.S. News and World Report" article "How to Forgive, and Why You Should." Other physical benefits include lower blood pressure and cholesterol levels.

Understand the Process

Forgiving is a process, and it takes work, according to clinical psychologist Ryan Howes in the "How to Forgive, and Why You Should" article. Give yourself permission to fully feel and express your emotions. Write them in a journal or a letter you don't send, maybe yell at the top of your lungs in a private place. After letting off some steam this way, tell your friend how you feel. Understand the why of it, whether from her explanation or a logical assessment of her behavior and what it says about her and the friendship. When you understand things on a rational, intellectual level, it helps drain the destructive emotions away. Find a way to feel like it won't happen again, such as accepting her word that it won't or changing your relationship with her to help ensure it doesn't. Then, just let it go. Don't talk about it with her, your other friends or your boyfriend. Let it be over.

Separate Decisions

Choosing to forget the wrong or to re-establish your friendship after forgiving, those are separate decisions from the actual choice to forgive. While you should forgive her for your own well-being, choosing to forgive in no way obligates you to just take up your friendship where it left off, as though nothing happened. There is a difference between no longer being angry and trusting a person to not hurt you again. A person who truly understands the hurt she's caused you -- an important factor in it not happening again -- cannot begrudge you the time you need to gradually return to friendship and trust.

Take Your Time After Forgiving

After doing the work of the forgiveness process, don't rush into decisions about what you want to do with the friendship. It's going to take time to see if the friendship can withstand what happened or if it even should. Get busy with other things, add new interests, activities and friends to your life. Be polite and reasonably pleasant when you run into her after you forgive and let go of the boyfriend-stealing attempt. Let your friend shoulder the rebuilding burden for a while. If this is a friendship that you both value, over time it can be repaired. If it's a friendship that has run its course, then smile and exchange the occasional casual greeting when you see each other in passing.