Found the following on a blog, "Ridding yourself of negative people". Everyone has to "clean house" now and again. The following really struck a cord with me.
"As human beings, we are given the freedom to hand-pick people that contribute to our well being and enrich our lives. We are not physically bound to anyone, and many of the people we interact with every day were not even our choices, but rather the product of our environments. We have no obligation to remain loyal to those who affect us adversely unless we place little value on our happiness."