Sometimes a relationship just needs to end. If they were being honest and I felt the same way, I see no harm in them telling the truth. When you're in a relationship that isn't going well, it is going to be too stressful to want to continue.
I guess it would depend on whether it was a serious relationship or a quickie. Serious, it would hurt. The later, wouldn't care at all. Actually, if I did the breaking up, I probably wouldn't care much in either situation really.