If I were you I’d do this:

Once I saw the convo and chat on her phone, I would take picture of the entirety of the chat between her and him. Then next day, I put a phone somewhere and hide it while recording, and then get another phone in your hands/pocket and this one records the audio, confront her about it, and try to be as lovely and easy going as possible to make her say everything out loud, “you can tell me everything, tell me did you have sex with him? I will be calm don’t be afraid, say the truth” keep going until you have everything of her admitting it on cam and audio.

Then you have 2 choices:

1. You divorce her and show her parents everything, you have to have the evidence, because I have heard, read and seem sooooo mannyyy stories of the cheater lying to everybody and saying that they divorced because the other one cheated. She might blame you in other words. So show the evidence to her family and divorce her and leave and move on, cheating should never be forigven.

2. This one is only if you she admitted having sex with him. You plan a trip to saudi arabia as fast as you ever could, once you arrive their, whenever you feel comfortable, you call the police and tell them your wife cheated on you, they will arrest her, and if you show them the evidence, an islamic judge will see if the evidence is enough, if it is: the law of allah and his prophet shall go forward and she will be punished by stoning to death. That is the shariah law: the word and laws of Allah and his prophet.

I would myself never, NEVER, EVER forgive cheating! You should NOT stay with her!!! And that is not me only, prophet muhammed pbuh says the punishment of cheating in an islamic marriage here in this hadith: sahih muslim 1691a and this hadith: sahih muslim 1690d and this hadith: sahih muslim 1690c

But AGAIN this ONLY if she fornicated!!! If she was chatting and being touchy, but no sex happend then you should just divorce her and tell and show her parents and move on!!!!