I am tempted to ask my child about what goes on in my co-wife's home. Is that wrong?

Making a child a source of information or a spy on the other household burdens their soul and teaches them to be devious. The wish to know is understandable, but it puts the child in an unfair position, trapped between two sides they love. If there is something you need to know, ask your husband directly, not squeeze stories out of your child. Let your child's relationship with their father and the other family stay free of your pressure. If your child tells you things of their own accord, listen without interrogating or reacting emotionally. Protect their cheerfulness from adult conflict. A child not burdened with secrets grows up calmer and more honest. See relationships between co-wives.