I am not aware of your exact sitch... But, I think you are taking the right path in general....
I would not worry about the "rebound" relationship.... I would actually encourage it.... I am not advocating you go out and sleep with a random woman..... I'm just stating a new romantic interest is fine....
People can talk all they want about being "alone" (very few people really are)..... People can talk about healing.... Healing is needed... But, what we really need is "good" people in our lives....
Back to the exW's good friend..... If your exW did really do "some VERY bad things during the course of our marriage"... I would see nothing wrong with dating her good friend.... I read in one men's magazine where they ENCOURAGED going after a woman in her circle or someone she was jealous of.... Now, if I were the one to leave my M (which would NEVER happen).... I would NEVER dream of hurting my ex like that....
RMG
"The bad things in life open your eyes to the good things you weren't paying attention to before." from "Good Will Hunting"