What should I do if I find my husband likes to chat with his sister?

What is the general content of your husband's chat with your sister?

If it is ambiguous, then you should pay attention. Talk to your sister first, see what attitude your sister has, and then deal with your husband.

If it hasn't happened, take preventive measures before it happens.

If your husband had anything with your own sister, don't be soft-hearted. It's time to leave. It's time to break up. People don't get involved with animals.