Question: what to say to a friend who is cheating on his wife?
Answer: Listen to your friend. “First and foremost, it is important to hear your friend out,” said Mudita Rastogi, Ph. ... 
Be honest. ... 
Don't minimize the affair. ... 
Encourage your friend to think about his or her actions. ... 
Be a friend to your friend's marriage. ... 
Encourage your friend to get professional help.