Dear Mr. Dad: I was divorced in 2001, when my daughter was 1. She’s now 11. Here’s my dilemma. The person who was a big part of the divorce is still with my ex. But up until recently, my daughter knew him only as a cousin. After all I been through, I resent him when my daughter talks with him or spends time with him. Do I just keep swallowing my pride and let it go, or is this something I can talk about with her in a subtle way. She understands that her mother and I were divorced but not that this guy was involved.

A: I totally get that you’re still angry with the guy your ex is involved with (and who, if I’m reading between the lines correctly, was involved with her before she became your ex). And you have every right to resent his proximity to and relationship with your daughter. But be very, very careful. As painful as it is, you’re going to need to swallow your pride for a while longer—at least until your daughter comes right out and asks why you and her mom got divorced. Given that she’s perched on the brink of becoming a teen, that should be pretty soon.

When that day comes, you can—and should—tell her the truth. But do it in as calm a way as you can. Do not come across as attacking anyone (and by “anyone” I mean your ex or her “friend”). Just lay out the facts—and make sure they’re facts no one can argue with. The last thing you want is to get your daughter involved in a he-said-she-said kind of thing. She’ll end up in the middle, and that’s a place she should never be.

Like it or not, your ex’s friend is a part of your daughter’s life, and you need to bite your tongue and support him. If you can’t bring yourself to be supportive, at least don’t do anything hostile or vindictive. There is absolutely no upside to that. The only thing that will come of it is that your ex and, most likely, your daughter, will turn on you, and you’ll become the bad guy.