A relationship doesn't all end up as a happy one. Sometimes we need to undergo problems and so many breakups before we can find the best of all those. What is the most important is one is sticking on what he or she is have, I mean not a collect and select type because not all are used to play. If there are gameplayers, there are also sincere ones who are at most hoping that the one whom they are dating is also sincere and expecting that she is alone.
I have understood that love needs to be watered everyday. I am so sorry for the sad experience that had happened to your friend, that was a lesson to be learned and hope that she learned she was not the only one who undergone break up. What I am glad about the guy was he had teh courage to tell the truth to the girl rather than pretending that he is still loving your friend though not anymore. If that was the case, that was even more painful specially when she found it too late or let us say she has just caught that her guy has already another one. He was honest at the last part and that was the thing that she must be thankful with as she wasn't fooled.
Yes I believe that it is very unfair when the partner is playing while the other is very sincere and making his or her best to make the partner happy. We can't control things that will happen to the relationship, it needs understanding, respect and many other values to make it work.
It is not a game indeed to play with it or a toy that it will be thrown after you are tired of playing with it. It is very different, it involves heart and ones feelings which is very sensitive. I have observe that there is no expert in terms of relationship in a way that when one is hurt he or she can't pretend she/he is fine. He/she is badly hurt specially when he/she gave everything she/he could just to prove how much the other meant to him.her.