Legally this type of case would be "defamation", meaning that it's a false statement of material fact, communicated to a third party, that causes quantifiable economic damages or is of such a nature that the allegations refer to criminal misconduct, sexual misconduct, or that the plaintiff has a sexual disease (this is called defamation per se).
Note that the statement has to be false. If it's true, this is not legally "defamation", even if it is harmful to someone's reputation. It has to be false to be defamation.
But it also has to be a "statement of material fact". That means that opinions are not actionable. Opinions (even if everyone else on the planet would say otherwise) would not be actionable. It would have to be a statement of fact (objectively verifiable, rather than something that is in one's opinion).
Further, it has to cause "quantifiable damages". The main issue here is that many lies and insults that would otherwise be actionable cannot show how the individual was harmed, to a reasonable degree of probability. So the courts require that you prove the actual dollar amount that she was harmed as a result of this. And that's often where these cases fail. Typically the only successful cases are where people lose jobs (lost wages could be proven) or do not get advancements in their jobs, etc...
So calling your wife the devil, untrustworthy, don't do business with her, etc... are all opinions. If she gives specifics ("she stole my purse" or something else objectively verifiable that was false) then that could be the basis for defamation. But they HAVE to be statements of material fact (that of course are false). And then you have to show the economic damages that have been suffered as a result of the statements. Past and future losses, and loss to reputation, could be quantified, but it takes pretty specialized knowledge and training by economists and other experts to do so. So it's already an uphill battle to even get to see how much damages you have from the statements, IF they're even statements of material fact rather than opinion.
And another consideration is even IF you get a judgment, how are you going to enforce it? Texas doesn't allow garnishment of wages, and if she doesn't have a ton of assets otherwise, she might be "judgment proof" (meaning that a judgment is only worth the piece of paper it's printed on).
Now IF you could overcome all of those issues, you could have a case, but it's not a great one from the outset. Given the right facts, the right amount of proof, and a good potential for recovery, that could be a case. But otherwise it might be simply throwing good money after bad. The best part of such a case, however, is that you can say that you sued her for defamation, and that alone could go a long way to showing (at least in the minds of the viewers) that she was lying.
I know this is probably not what you wanted to hear, but it is the law. I hope that clears things up anyway. If you have any other questions, please let me know. If not, and you have not yet, please rate my answer AND press the "submit" button, if applicable.
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