Flushing friendships

I am ending a friendship that was very important to me in the last year. It just doesn't serve me anymore. I know this sounds cruel, but when a relationship begins to be unbalanced and one person is giving more that the other, its time to end it. Energy and time are precious commodities to me. Relationships are suppose to give as much as they take. I know we are all surrounded by people that we would like to "flush". Just remember the toxic drain does untold damage on other relationships we have, not to mention the time wasted thinking and strategizing about them (strategizing is a word used in war). Is there a secret to ending this relationship in kindness and letting them go? Here is my opening line... Its not you, its me.... Wish me luck.