Legal Question in Legal Ethics in California

I am sorry to hear of your situation.

There is no action within the courts that you can take to stop the affair. The only action that you can legally take is to consider a divorce.

Mr. Perry is entirely correct. It has been over 50 years since California, and most other states, decided to get out of the business of people's relationships. So we instituted no-fault divorce, and eliminated all legal proceedings for anything to do with adultery, alienation of affection, etc.