Q: My question involves the “guest list” for a retirement party. The retiree was my husband of not quite two years. The party was planned and executed by my stepson, who is 32, and was held at my home. Without my knowledge, my stepson informed his mother, the retiree’s ex-wife, about the party. Not only did she choose to attend, but she brought her boyfriend, the alleged reason for the dissolution of a 31-year marriage (about four years ago). In my mind, it would be one thing for my stepson to mention the occasion of the retirement party. However, it is quite another thing for the ex-wife to attend, and to bring her boyfriend just added insult to injury. What would have been good ex-etiquette?

A: Although it appears what really upset you was that your husband’s ex showed up at your party, all this could have been avoided by handling the guest list properly. If you and your husband compiled the guest list, then your stepson, as the party planner, should have followed that list to the letter. If he was given carte blanche, then he should have compiled the guest list, but run the list by you prior to mailing any invitations. And, finally, it’s not surprising that he mentioned the party to mom, but when he found out that she was serious about attending — and that she was bringing her boyfriend — he should have run that fact past dad to make sure their presence would not offend him. If dad didn’t want his ex there, he would have then had ample time to make that clear to his son, who could have then explained to mom that it would be awkward if she attended.

I find it strange that a man of 32 years of age would have no idea that the presence of his mother and the man who broke up his parents marriage would be inappropriate at a party held in his father’s honor at his father’s home so soon after his parents’ breakup. Of course if Dad gave his son the impression that he holds no ill will toward mom, then it could be understandable, but your reaction tells me there is some unfinished business that needs to be addressed.

It sounds like dad needs to establish clearer boundaries concerning his son’s mother — with his son — and you as well. Considering Ex Etiquette rule No. 5, “Don’t hold grudges” may be helpful, and Rule No. 6, “Don’t be spiteful,” is a necessity if exes (and their new partners) are to progress to “bonus” status.

Finally, following good ex-etiquette is not just for those who break-up, it’s for everyone. Ex-etiquette rule No. 9 is “Respect each other’s turf,” and in this case the son did not respect his parents’ turf. It’s important that divorced parents never try to celebrate together before they’re ready — and children, no matter their age, should not try to interfere in order to hurry the process. It often backfires.

Dr. Jann Blackstone is the author of “Ex-etiquette for Parents: Good Behavior After Divorce or Separation,” and the founder of Bonus Families, www.bonusfamilies.com. Reach her at:

drjannblackstonegmail.com