Q. I don’t trust my child’s father. He says one thing and does another — all the time. I get to the point where I think maybe, just maybe, I can trust him and then he pulls something that makes me furious. Most recently I found out he is taping when we exchange the kids to use against me at some point, but last week he was telling our co-parenting coach how much he appreciated my honesty. It’s maddening. What’s good ex-etiquette?

A. Good co-parenting is based on trust. Actually, just about every ongoing relationship is rooted in trust. But when it comes to the custody of your child, you have a court order saying you must share your children’s time and negotiate any changes in good faith. You can’t tell anyone about their shenanigans because that’s badmouthing, and you are chastised for being on the defensive because that’s holding a grudge.

Meanwhile your kids are getting older by the second and watching how you both interact with the other person, who they love as much as they love you.

So, how do you cope with a co-parent’s dishonesty? You must stop reacting. Stop allowing their behavior to control your responses. In other words, decide what is the correct action —not reaction — to a situation and then follow through.

For example, taping your exchanges is underhanded. But now that you know, would you act any differently if you were being taped or not? If the answer is yes, check that. If the answer is no, all taping will do is prove that you are polite, accommodating and won’t take the bait when provoked.

More importantly, it’s the mindset behind taping that I find troublesome. Good Ex-etiquette For Parents Rule No. 8, “Be honest and straight forward,” is a rule for a reason. Every conversation we have with our co-parent sets the stage for the next conversation. If it is rooted in honesty, you are putting your kids first and tapping into your higher self. 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.”/Tribune News Service