Q. My ex is not a good person. She sends me terrible text messages that the kids have read over my shoulder. They tell me she refers to me as “sperm donor” when she talks to her friends. (They aren’t sure what that means, but they know it’s bad.) Now the kids are telling me they don’t want to go back to her home. We alternate weeks, and this is a real problem. What’s good ex-etiquette?

A. When a co-parent badmouths their co-parent in front of the kids on a regular basis, one of two things can happen. One, the kids begin to identify with the badmouthing parent and follow suit; or the more common response, they reject the one badmouthing.

Children don’t want to hear all the negativity, especially about someone with whom they share DNA. Add their split allegiances because they most likely love the badmouthing parent too, and the only thing they can think to do is opt to stay right where they are. That’s when you hear, “I don’t want to go back.” If they are with the badmouthing parent at the time of the badmouthing, they are planning their escape.

So, what constitutes badmouthing? Referring to their father as “sperm donor” borders on emotional abuse, but there are less negative references that could upset your kids — sometimes because they aren’t sure of what is meant by the reference.

Co-parents grandparents, must be very careful about the references they use. Children personalize everything.

When you hear a child repeat something questionable that happened at the other home, make a phone call. Don’t accuse; ask for clarification so you can reinforce the positive or clarify what was said. That’s good ex-etiquette.

Dr. Jann Blackstone is a child custody mediator and the author of “The Bonus Family Handbook: The Definitive Guide to Co-parenting and Creating Stronger Families.” She can be reached at www.bonusfamilies.com or jann@bonusfamilies.com./Tribune News Service