DEAR ABBY: My ex-husband and I have been divorced for three years and share custody of our 10-year-old daughter, who lives with me full time. Her father lives out of state and sees her during the summer months. Last year my daughter had an incident (an “I’ll show you mine, you show me yours” kind of thing) with a friend at school, and my ex and I decided they should no longer hang out after school alone anymore. A year has gone by, and because they’re in the same social circle at school, my ex is refusing to allow her ...