Processing her grief and pain, she reached a point when she realized that she had to require something from her husband in order to heal. It's "get help or get out." She became so anxious and frightened about the possibility of her husband leaving her and cutting his support if she requires him to get help and rehabilitate. In the end, she chooses not to confront her husband. She chooses to look away.
"Betrayal blindness" is a state of mind in which you choose to keep a secret from your self. You have it when the reality that's happening in your world and the consequences of that reality are actually more frightening than you walking in through it to heal. So, in essence, you lie to your self. You turn a blind eye. You don't look at what's actually happening because it would cost you too much.
Indeed, we can be too afraid to look at and embrace truth. As a result, we choose to stay sick instead of heal. We tolerate the intolerable because we don't want to deal with the ramifications. It's "betrayal blindness," one of the most horrible bites one may suffer from away from recovery and wholeness.