Q: My stepdaughter is turning 13 and we were going to have separate parties, but her mom wants to have one party. I don’t respect her or trust her and I think the reason she wants to have one party is so my husband and I will pay for everything. Is it right to not want her in my home and co-party? What is good ex-etiquette?

A: Rule No. 1 of the 10 rules of good ex-etiquette is, “Put the children first” — and nowhere in your question do we see or hear what your child wants.

That said, it’s your right to have anyone in your home you would like, and if that means you would rather not invite your husband’s ex, then that is your prerogative.

However, if you have already decided to have the party in your home, inviting everyone but her would be extremely bad ex-etiquette. Better to have the party in a neutral location.

The truth is, we rarely suggest parents who are no longer together celebrate together unless they feel comfortable doing it.

If you are not ready to hold out the olive branch, the ex coming to your home could feel like you’re being invaded by the enemy. This does not make for a happy birthday party.

We learned about this all firsthand because initially we rarely celebrated together.

The kids cleaned up with two of everything — two Christmases, two birthdays, but also secretly confided that they wished Mom was at Dad’s party and Dad was at Mom’s party.

Since Jann was always around and witnessed the disappointment firsthand, it wasn’t difficult for our bonus family to transition into one big party at the local bowling alley because it was obvious that is what the kids wanted.

In fact, “Put the children first” turns out to be a great tool for problem-solving. The first thing you look for when resolving any conflict is common ground. And what all parents share, whether they are together or not, is their love for their children. If you use the love of your children as the criteria for making a hard decision, ultimately you solve the problem.

If you choose to co-party, agree beforehand how expenses will be covered. However, once the party is removed from your home, splitting the bill will seem like a more obvious solution. Both parties agree to save receipts, both present the receipts for what was purchased, and split the cost.

Finally, when approaching your husband’s ex, consider ex-etiquette Rule No. 3, “No bad-mouthing.” Even if you don’t respect your husband’s ex, you have to treat her with respect in the presence of her child. Even innuendo is inappropriate. Everything is always done in the best interest of the kids.

Jann Blackstone-Ford and her husband’s ex-wife, Sharyl Jupe, authors of “Ex-Etiquette for Parents,” are the founders of Bonus Families (www.bonusfamilies.com).