I have very little to do with her because I think she is much like that. I've seen her 'stab' her friends in the back too many times. I only deal with her when work calls for it and I try not to get drawn into any real conversation with her. I often turn the conversation to asking about her grandchildren and that subject keeps her busy. :P
I'm so sorry you had an ex like that.
No worries ... he was a very good learning experience and as you can imagine we did not last long. Alas he continues to 'mine' other unsuspecting females. To your Lady B ... do as you do ... keep her sweet:)