According to the woman, her partner's mother, who she called Becky, often made "snide remarks" about her parents' blue-collar jobs and her job in nursing.
Things reached a pinnacle at the airport after she realised Becky had purchased first-class plane tickets for seven other people in the group, while she was left to fly in coach.
According to the post, Becky wasn't shy about explaining the reason why.
"She told me I was used to it and she had a free coach ticket so I should be grateful for going," wrote the woman.
"They all did their express check-ins and left me in the long line for me to think about what the heck is going on.
"I had to keep from crying the whole time in line. I got up to the counter and there was a baggage fee for me. My boyfriend at the time never once helped me through the coach line or said anything to his mom".
NoTGoingThank continued: "I looked over at his mum's smug face as I was about to pay the checked baggage fee. And I let all of my frustrations out on the attendant and started crying."
After her tears were ignored by her boyfriend and the check-in staff said she shouldn't go with the family, she promptly broke up with him and left.
When asked whether she was in the wrong for the breakup, more than 30,000 people responded, with most supporting the woman.
"The fact she got seven (7)!!! other people first class tickets and yet magically the budget ran out when it came to you tells you everything you need to know," wrote one person.
Another responded: "Your boyfriend's entire family is absolute trash. Pure toxic garbage."
"Breaking up with him was the best thing you could have done for the peace and happiness of your future self," wrote a third.
Many also called out the check in lady, calling her the "real MVP".