Memories of past betrayals impact on current ones. The more betrayals, the stronger the impact. The betrayed woman must recognize this connection. Once she does that, linking past to present, she will be free to focus on the current situation. A betrayed wife feels devastated because the marriage is no longer the safe haven she thought it was.
Some women move into self-blame pointing the finger inwards.
To help herself she can identify and accept her feelings and recognize that her spouse's affair was his choice and may have had nothing to do with her per se. The woman who turns her anger against herself does this becauseit is familiar to her. A better way is to read the message in the affair and direct your angers where they belong. That will help put energy wasted on self-blame or depression into positive steps to take, such as repairing the marriage or leaving it. Those are the positives.