Yes she did have an affair with her director, but Robert did take Kristen back, because he feels that no one else can understand his life, the way that Kristen understands it. They are back together, but they're waiting a few months to announce the news to everyone.
Yes, she had an affair. Robert moved out of the home they shared however, he forgave her, they are back together and living together. Everyone in the entertainment industry is aware they are back together.