Can somebody really just stop loving you after 8 years together when they meet someone new after only six months apart?
The person may have been discontent in the relationship and just hadn't said anything. A lot of people also can't deal with the strain of a long distance relationship either--it's easier for them to be with someone they can regularly see than someone they phone or email, but don't see much of physically.
Meeting someone new gives a person a sense of excitment that they may have felt was missing in a long term relationship. People often have affairs for this reason.
In the long run it doesn't matter, because if the person doesn't want to be with you anymore, you shouldn't have to change their mind. It's better to find someone else. The best thing to do is to accept what happened, and move on with your own life.
No, love is a choice. They can choose not to love you, but it doesn't just happen.
NO. Just because they began a new relationship, does not mean that they do not love you anymore. Maybe they just couldn't do the relationship anymore. 8 years is a long time to work on a relationship that is not working, whether you love each other or not.