WhatHappened, I really like your philosophy on this issue.
My husband really wants to think the best of people he cares about, so when partners of his have belittled me, he tends to either not recognize that it's taking place, or else he defaults to "Poor dear, she's just upset, when she calms down, she will regret saying these things, so they don't count, do they?"
Rory, I won't go into the particulars of our situation too much, but my husband's girlfriend called me a selfish bitch in an email to him, and was almost as insulting to me directly. He didn't react to it at first, not until he shared the email with me and I hit the ceiling. He has since set a firm boundary with her about insults, etc., and asked her to apologize to me. She has not, but it's only been a couple of days since his request.
What makes this all the more complicated is that their relationship is part of a quad. I am involved with the girlfriend's husband. I am very worried that she won't let my boyfriend and I continue in our relationship without a lot of pushback from her, especially if my husband breaks it off as I think he might. Boyfriend and I are an established, loving relationship of almost a year, and we have been happy together for the most part, but if she continues to stir up trouble, I don't know if my boyfriend will assert his right to stay in the relationship with me, or not. I guess if he doesn't, maybe it wasn't meant to be.
Nycindie, I had to laugh at your comment about high-school behavior. The woman in question is in her 40s, and has a Ph.D from Stanford. I guess some people never do really mature past high school though.