What should I do if I find the ambiguous chat record between my wife and my first boyfriend?

first of all, you should be calm, having an affair with your first boyfriend. I think you must deal with this matter well and observe it first. If you find this kind of phenomenon again, go to her again, and you can't do it again and again. Since she chose you, you should choose to trust her. If she really has something, you already know that she didn't say it twice, and the third time she has nothing to say. Personal opinions are still expected to be adopted.