Knowledge of Cheating Situation

I work in a role where i have access to employee records at a large company (wo dering why thats relevant? READ ON) and my good friend works there also. She is in a failed marriage and told her partner she wants a divorce. Her and another employee have a spark and she is falling for him.. here's the problem.. he is in a relationship with someone and they have a 2 year old together. She told me that this man has, on multiple occasions come and passionately kissed her. He has also been sexting her, telling her he's not happy in his relationship but stays for the child. She has told him that she is falling for him and that it's not fair to do what he's doing and she won't be a home wrecker (good on her) yo which he told her he was torn. My question is.. as I have access to personnel records, I have his partners phone number.. do I butt out or find a way to secretly and anonymously tell her? Please note this man's previous relationship failed due to him cheating WITH A WORK COLLEAGUE. HELP!? What would you do? 😟