The critics hated this song when first released, but there's a reason why this tune is so popular. It touches on a common experience, feelings of loss and the grief that accompanies being replaced in a relationship. 

That's according to Dr. Randl Gunther in an article for Psychology Today, 

Displaced, Replaced, Erased

The Anguishing Heartbreaks of Rejection

The opening paragraph reads, "Of all of the possible experiences people endure when they are abandoned in love, rejection is probably the most painful. Once felt beloved and valuable, they are understandably demoralized and broken when they are no longer “necessary” in another’s life. A once familiar and treasured experience turns into a terrifying, seemingly endless nightmare."

"Many times, the warning signs that could have predicted the loss were not obvious or denied. When the partners who are done leave the relationships, those left behind must face not only that humiliation of “being the last to know,” but the additional sense of powerlessness that accompanies a “done deal.” They are not only abandoned, but robbed of the chance to fix what is broken."

In her experience as a therapist, Dr. Gunther says the most commonly asked questions are:

1) How did I not see his discontent?

2) How could I have been so attached and not realize she was disconnecting?

3) What could have led me to believe that our relationship was still so valuable, when he obviously didn’t feel that way anymore?

4) When did we start falling apart?

5) What were the warning signs I didn’t see or didn’t want to see?

6) Why did she run away without giving us a chance?

7) Did he ever really love me?

8) Is her new partner just a better deal for her than I was?

9) How could I have done this differently?

"By the time a relationship ends, those questions can never be adequately answered. There is too much guilt on one end and grief on the other."

Matthias Roberts put it this way, "Being cut off from [an] Intimate relationship affects every other relationship in our lives."

You can move on, adapt, once the grief heals. The feeling of loss never goes away entirely. But you can adapt. At that point, you can rebuild by learning from the experience, and develop healthier relationships. Don't be afraid to ask for help. Lean on the support. Above all, take it easy on yourself.