I'm appalled by my son's behaviour towards his wife. I thought he was having an affair, but this deception is so much worse. Should I keep his secret? BEL MOONEY answers a moral dilemma that would floor any loving mother

Dear Bel, I have a question that is not unusual. Do I tell - or not? My son has been married for 23 years, with two adult daughters. A few months ago he left home and is now talking of divorce.