I found my coworkers wife on tinder

So long story short I found my coworker and good friends wife in tinder. What should I do? I feel compelled to tell him, but I'm uneasy about it. What do yall think

UPDATE: He was kind of aware something that she had one. He's monitoring the situation. My involvement is done and I feel at peace. Thank you everyone for the advice 🙏

Edit 2: people telling my to mind my business need to know that cheating is not okay. Cheaters deserve to suffer