Man, what would lead a person to be someone's best friend and lover for 10 years, being very good to that person throughout that time period, to just all of a sudden cut the person out of their lives and sever all ties and affection? That's cruel. I could never do that to someone.
I have wondered that very same thing and still don't have an answer. Mine ran because her past affects her present. But, still that's no excuse. I just don't know how they'd just so coldly turn on us. Like you, she was my best friend and lover. I had no idea it was coming...sigh. I guess some questions will never be answered.
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.