Q. My husband and his ex share equal custody of their kids. However, she calls constantly, whether the kids are here or not. We have asked repeatedly, politely and firmly not to call except in cases of emergency, but today she called to tell my husband that William lost his first tooth. A tooth? He’s got tons of them! It’s driving me crazy. What’s good ex-etiquette?

A. Sounds like you are expecting to have very little interaction with his ex and if mom and dad are co-parenting, that is completely unreasonable. They SHOULD be calling each other — everyone (including you) should be doing their best to follow the first rule of good ex etiquette, “Put the children first.”

Personally, I think mom was acting appropriately by calling dad about their son losing his first tooth. I think she should have texted him, as well, and included a picture. Losing your first tooth is a big deal and definitely something that should be shared by co-parents.

It also sounds a little like you may be dictating policy in your home, and if that is so, be careful. Ex-etiquette rule No. 4 is, “Bio parents make the rules, bonus parents uphold them.” If you are attempting to set precedent, you may alienate these parents and you’ll set yourself up as the outsider. Your husband has a past that is very much part of his present.

Even though I support you in your need for privacy, to get that privacy you must be very clear in communicating your boundaries — and your husband is the one to do it, not you. Etiquette rule No. 9 is, “Respect each other’s turf.” If he’s sending mixed messages, that could explain his ex’s persistence. Your husband must be clear about what he expects from this co-parenting relationship and while doing that he can also reiterate your importance.

That said, if your husband has made the boundaries clear and she’s still calling with unimportant information, it’s time to use voice mail.

Finally, you may also need to adjust your attitude a little, as well. That’s good ex-etiquette.

Dr. Jann Blackstone is the author of “Ex-etiquette for Parents: Good Behavior After Divorce or Separation,” and the founder of Bonus Families, bonusfamilies.com./Tribune News Service