There comes a time in every family when the parents-and-children holiday stops becoming the norm.
For some, they simply stop taking holidays with each other altogether. For others, the tradition continues, but as the kids grow up they ask to bring their partners along as an extension of the family unit.
As for the latter, one mum who planned a trip to Greece with her 30-year-old daughter is in this predicament and has written about her dilemma in the New York Times.
While she wants to spend quality time with her daughter, the daughter wants to bring her boyfriend along for the trip.
There's just one complication - her boyfriend is married to someone else.
Writing to the NYT's advice page, the mum expresses her despair at her daughter's relationship, explaining her daughter is dating the man, who is polyamorous.
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She writes: "She brought him home for the holidays, and while he was charming, I felt uncomfortable. (This may have been triggered by my husband’s infidelity that led to our divorce)."
Now, as she plans the big trip to Greece, the daughter wants to bring her lover along with the family - but this doesn't sit well with the mum.
She writes: "It may be petty, but I don’t want to foot the bill for another woman’s husband. And I don’t see any way this relationship can lead to my daughter’s happiness."
The despairing mum asks if she should put her foot down - and risk her daughter not wanting to come on holiday either.
Do you have a relationship dilemma? Email jessica.taylor@reachplc.com.
In response, agony uncle Philip Galanes suggests the mum's issue might not be with her ex's infidelity or concerns about the cost of the holiday.
Instead, he asks her if she's projecting her own idea of a happy relationship onto her daughter, which he said is a "common" thing for parents to do.
He also points out that, if the daughter's boyfriend is in a polyamorous relationship, then he isn't cheating on his wife by having a girlfriend too.
The columnist advised the mum to read up on polyamory as a concept, to understand a little bit more about how it works.
He writes: "I am not suggesting that you set aside all of your concerns — only that you try to respect your adult daughter’s decisions."