Q: My husband and his ex share their kids equally, but she tries to upset our family every chance she gets. I get along great with the kids, and for the past four years, I have taken them out to buy presents for their dad. Last year without asking me, his ex bought my husband a present from the kids: a Chiefs jersey (he’s a Chiefs fan). He loved it, but I forbid him to wear it because I know who really bought it. It wasn’t the kids. It was her! Am I being petty? What’s good ex-etiquette?

A: Yes, you’re being petty — and if you have to “forbid” your husband to do anything, you have bigger problems than his children’s mother buying him a present.

Know this: Your husband has children and an ex-wife. If she doesn’t cooperate, being vindictive will do little to defuse the conflicts you’ll face. Of course she bought the jersey, not the kids, just as you have bought the present for the previous four years. It was never about who bought the present, but the unselfish act of buying it. Your actions are not teaching the kids to look for solutions when facing conflict. Your actions are teaching them to be spiteful and perpetuate conflict. That breaks all 10 Rules of Good Ex-etiquette for Parents, starting with Ex-etiquette for Parents rule No. 1: “Put the children first.” You are not.

The responsibility of buying presents “from the kids” usually falls to the bioparent unless the responsibility is relinquished to someone else — which it sounds like it was since you had been doing it for four years. The problem seems to be that a precedent was set, and when the kids’ mom changed her mind without consulting anyone, it upset your tradition and you felt your importance was diminished. It’s understandable that you’re upset. It still doesn’t let you off the hook.

A better way to approach this would have been for the parent figures to talk to each other. Yes, you and Mom. It would be helpful if they saw positive interaction between two very important people in their lives. You and Mom don’t have to go shopping together, but you should be able to simply touch base to coordinate efforts.

Help pave the way for new beginnings no matter when they start. In the name of the children.