Question: My husband is still in love with his ex. He says he’s not but I think he’s lying. Evidently, she cheated and he left, but when she drops off the kids, he insists she come to the door. Sometimes he invites her in while the kids get their stuff. When he can’t pick up the kids, she’s the first one he calls — never me.

They celebrate the holidays at my husband’s parents’ home, and it drives me crazy that she’s at every big holiday. He says they’ve always done it for the kids, but I think it’s more. The kids can see it, and last time she left, the littlest one, who is 5, said, “You don’t like my Mommy, do you?” I didn’t know what to say. What’s good ex-etiquette?

Answer: If your resentment is so obvious that a 5-year-old can see it, it’s time to make some changes. A child says something like that to you, even if you hate the ex’s guts, you find a way to ease the child’s concern. If it’s any comfort, you’re not alone. Ex jealousy is one of the most difficult problems to overcome.

Have to say it: Some of the things you mention are not necessarily indicators of leftover love. If the kids are 5-ish, wanting the other parent to come to the door when they return home is good judgment. And, inviting her in is polite if she’s waiting outside. Why would you treat her any differently than you would treat anyone else in that situation … especially if the kids are watching?

Next, being available to pick up the kids when the other parent can’t, again, is not an indicator of love for the parent as much as it’s an indicator of love for the kids. It’s rule No. 1: putting the kids first.

The first person you should call is the kids’ other parent. It’s understandable that you’re upset that your husband doesn’t call you. That will come in time.

So, the holidays are coming up, and you’re dreading spending them with her at your husband’s parents’ home. It sounds like that was their practice before you came into the picture. Getting in the middle of well-established tradition can cause huge problems for a new marriage, not to mention resentment from family members that might be difficult to undo. Of course, now that you are married, things can certainly change, but go slow and be patient.

Finally, even if he told you she left him and he cried for years, dwelling on that sort of information will just eat at you. When you’re faced with being angry or resentful, just remember, resentment is letting someone live in your mind — rent free.

So, stand back, take a good look at exactly what’s happening. Sounds more like she’s trying to be a good co-parent than a love connection. 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 bonusfamilies.com. Reach her at blackstone@gmail.com.