AITA for telling my son that my relationship with his mom is not his business?

A divorced father maintains a close, platonic friendship with his ex-wife after their split years ago. They’ve both remarried, their new spouses get along well, and the families spend time together comfortably. The ex-wife and her husband even asked the father to be a sperm donor for their youngest child (now 4), who is biologically his but raised by the ex and her husband.

The couple plans to welcome a new baby next month, with the ex-wife attending the birth. While the 10-year-old son is happy about the blended harmony, the 13-year-old has started expressing discomfort, calling the frequent hangouts “weird” and asking his dad to stop. When the father told him the relationship with his mom is “none of his business” and he should “deal with it,” the ex-wife suggested an apology, but the father refuses, viewing his son as a “brat” trying to dictate his friendships.

‘AITA for telling my son that my relationship with his mom is not his business?’

The parents have built a healthy post-divorce friendship.

The families are unusually close, including a sperm donation.

The older son is now struggling with the dynamic.

This situation highlights the emotional complexity children can face in unusually amicable post-divorce arrangements. The parents have created a healthy, cooperative co-parenting dynamic — rare and admirable — but the 13-year-old son is at an age where he’s processing big feelings about family structure, identity, and belonging. What makes the story more complicated is that the biological tie to the younger half-brother (via sperm donation) adds another layer of confusion for a teenager already navigating divorce, remarriages, and blended family life.

Telling a child that a parent’s relationship with the other parent is “none of his business” dismisses his valid emotions. At 13, he’s old enough to notice the unconventional setup and feel unsettled — perhaps longing for the “normal” nuclear family he remembers from early childhood, or worrying about where he fits in this tight-knit group. Calling him a “brat” for expressing discomfort shuts down communication instead of helping him process it.

The father is right that his friendship with the ex is his own choice, but as a parent, he has a responsibility to help his son navigate complicated feelings rather than demand he “deal with it.” A calmer conversation validating the son’s confusion while explaining the friendship’s boundaries would better serve the relationship. The ex-wife’s suggestion to apologize isn’t about weakness — it’s about modeling empathy and emotional maturity.

Here’s the comments of Reddit users:

The majority of commenters label the father YTA, criticizing his dismissive response and lack of empathy toward his son’s understandable confusion.

Many emphasize that the son’s feelings are valid and deserve a mature conversation, not dismissal.

A smaller group finds the overall arrangement unusual and potentially confusing for the children.

This post highlights how even the most positive post-divorce arrangements can still create emotional challenges for children as they grow older and become more aware. While the parents’ friendship is healthy, the 13-year-old’s discomfort deserves empathy and open discussion — not dismissal as a “brat.” Most agree the father’s response was unnecessarily harsh.

Have you ever struggled with a parent’s new relationship dynamic after a divorce? How did your parents handle your feelings about it? Do you think kids should have a say in how much time their divorced parents spend together? Share your experiences below.