HD, I've always found that most mean people (or those with mean streaks) are insecure and terribly afraid of being found out to have weaknesses.
What I'm not so sure about is how to deal with these types of people. Expose them with irrefutable proof that they do indeed have weaknesses? Play the game with them that they are flawless? What?
Good luck to you and I hope that the MC addresses this with her soon. If we all only had to live up to our marital obligations when the other person was deserving there wouldn't be many intact marriages. How many times am I deserving of my husband's love? Not many. How many times does he give it to me anyway--that's how you quantify LOVE.