1. Lack of communication: If there is no effective communication between husband and wife, the wife may have given up trying to change her husband's behavior or seek a solution. She may feel helpless and disappointed, so she no longer cares about her husband's infidelity.

2. Indifference or lack of love: A wife may always be indifferent or unloving to her husband's feelings, so she has no feelings for her husband's cheating. In this case, she may have lost her enthusiasm and expectation for marriage.

3. Trust: If a wife's loyalty and trust to her husband are seriously damaged, she may feel that she doesn't care about her husband's infidelity. She may have given up her marriage, or she is considering a divorce.

4. Accept the reality: The wife may have accepted that she can't change her husband's behavior and realized that she can only control herself. In this case, she may choose not to care too much about her husband's infidelity, but to focus on her life and happiness.

In either case, communication and understanding between husband and wife are the key to solving the problem. If two people can honestly communicate each other's feelings and needs and find a suitable solution, it will help to improve their relationship. If the problem cannot be solved, they may need to seek professional help or consider divorce.