Dear Amy: My husband and I have two close friends: “Jack” and “Katrina,” who are married to each other and have two children. We are often with them and with other couples at social functions. I recently found out that Jack has been in a multi-year affair with another much younger friend of ours, “Martina.” I spoke to both Jack and Martina and told them they need to come clean with Katrina. They haven’t done that and continue their affair in secret.