To be honest, having seen Mr & Mrs Smith, I believe their version of events. That there was a huge attraction between Brad and Angelina. If anyone did the wrong thing, it was Brad for not sticking to his marriage and staying away from Angelina. I can imagine that if he "confessed" the attraction to Jen it must've been awful for her. And that is Brad couldn't just leave it and stay loving Jen, then they had to split.