In a post shared on Saturday on the popular discussion site Mumsnet, user 5thHelena explained: “We are having a family meal out next week to celebrate a milestone birthday (one of the kids). Guests are me, my ex-husband, his wife, and our three adult children. It’s going to be an expensive night out with lots of fizz flowing. My query is how do we split the bill?”

She explained that they would both want to treat their kids to dinner, so splitting the bill six ways is not an option. But the mom was upset at splitting the bill in half between her and her ex and his wife.

“My ex and his wife each earn a decent salary, as do I. But there are two of them and one of me,” she wrote.

“The last thing I want to be doing is getting my calculator out at the end of what should be a lovely evening,” she explained.

“But I don’t really see why I should be subsidizing my ex’s new wife’s evening out. I just can’t figure out the maths and definitely don’t want to appear stingy. [I] would love to hear anyone’s thoughts on this.”

In fact, recent research shows that many diners don’t choose to split the bill after a group meal. In a survey by money site Mint by Intuit, nearly half of millennials revealed that they ask for separate checks after a group dinner.

Meanwhile, two-thirds of those surveyed don’t choose to split the bill evenly, instead choosing to pay for their own food only.

But despite the mom explaining her upset on the discussion site, Mumsnet users were quick to tell her that she was in the wrong.

“I’d split the bill in half,” wrote one commenter: “They’re half yours and half your husband’s children.”

Another reply said: “Sorry, but I think you’re being a bit petty about this. I’d just split it in half, even if it means you are paying half of your Ex’s partner’s bill.”

“It’s your kid’s birthday yes? This is a birthday meal to celebrate them and you and your ex-husband want to pay?” asked one commenter: “Surely you just split the bill between you and him. She isn’t responsible for paying for your kids’ treat.”

Lots of other responses on the viral post suggested that they split the bill so that the adults pay for themselves, and the two parents split the cost of the children’s meals.

Meanwhile, another commenter pointed out that the new wife would be paying toward the meals for the kids too: “She shouldn’t have to pay for the kids as they are your and your ex-husband’s.”

In a later reply, the poster updated with her thoughts after reading responses from Mumsnet users: “I know I’m coming across as petty and churlish… which is why I’ve come here to complete strangers for their opinions. But she seems nice enough and I just want to enjoy the evening so I think going halves is the right thing to do.”

Last week, another parent captured attention online after their adult daughter revealed her upset over perceived favoritism when he gifted her brother a $900 bike for his birthday after only giving her a card.