I'm Lucy, and I'd be happy to answer your questions today. I'm very sorry to hear that this happened.
Pennsylvania unfortunately abolished these types of causes of action many years ago. Now, the only action a person can take against a cheating spouse is to file for divorce. Because your wife cheated, you do not need to wait through the separation period before filing - you can file a fault-based divorce. You can ask the judge to deny her alimony since she broke up the marriage through infidelity. You can ask that she be required to repay the marital estate for any money she spent on the affair, which could result in you getting more than 50% of the marital assets. But I'm afraid you cannot sue the man involved, and he is not a party to your divorce. The case here is against your wife, because she is the one who made a commitment to you by entering the marriage in the first place.
A local attorney can subpoena phone records for you, including text messages, if you're planning to file for divorce. You do not need a lawyer to file, but you would need one to get those records now. If you're OK waiting until after the divorce has been filed, you'd be able to get a blank subpoena from the clerk of the court and serve it on the phone company yourself. You're also allowed to schedule depositions for both your wife and the other man in order to get more information to handle the case. That's also done after the divorce is filed.
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