Donna,

There you go again believing the lies he tells you. He had sex with her because you wouldn't give him time and space? BS!! He had sex with her because he was alone with her, his penis was hard, and she was willing. You didn't figure into it at all. If anything you gave him too much time and too much space. He is just blaming you for his affair because you are an easy target and he can't take responsibility for his own actions.