We have become terribly vulnerable, not because we suffer but because we have separated ourselves from each other. A patient once told me that he had tried to ignore his own suffering and the suffering of other people because he had wanted to be happy. Yet becoming numb to suffering will not make us happy. The part in us that feels suffering is the same as the part that feels joy.
Some relationships just don't work out, no matter how bad both parties might want them to. Sometimes time, distance, and circumstances get in the way. And sometimes we have a purpose for our lives that couldn't be fulfilled inside the bounds of that relationship.