I had a friend like that, too. When she wore me out, she no longer wanted me as her friend because I wasn't GIVING! I wound up in the psych ward because I gave so much!! I don't need to deal with that stuff anymore. I refused to be her friend again after she figured I had recovered.

As for being calm and polite, I've been that way too long. That's what finally drove me over the edge. He allows himself to act out his childish tantrums but I always have to stay cool, calm and collected and never have ANY reason for being upset with HIM. It's over. I've had it.