In a post shared on Mumsnet’s Am I Being Unreasonable (AIBU) subforum under the username AlenaMacc, the woman said: “One of my closest friends is celebrating her 30th birthday this Saturday,” and she was invited to the party. “I live abroad so it was amazing luck that I happened to be here for it.”

The friend later remembered AlenaMacc’s ex would be at the party and asked whether she had any issues with it, to which the user replied, “None whatsoever.”

However, the friend said the ex “apparently has an issue” with the user being there and asked for her “to come earlier and leave before he arrives.” The user told her friend that this wasn’t a viable option, as it coincided with her baby’s dinner, bath, breastfeeding and bedtime routine.

The original poster said: “She’s not close to my ex at all whilst me and her are very very close so I expected her to say ‘okay then, just come as we discussed originally…however, she then told me ’that’s okay, we can meet on Monday instead.’'

The user said: “I feel betrayed, I feel like she chose my ex instead of me, I can’t believe that she essentially uninvited me from her 30th because of someone whom she only saw once recently…am just overreacting. AIBU?”

An April 2019 study on the effects of rejection by a friend for someone else on emotions and behavior found that “rejection by a best friend, and especially comparative rejection by a friend, felt worse than other conditions.”

The study, published in the peer-reviewed journal Frontiers in Psychology, also showed that while people believe “they would feel worse after being rejected by a friend, positive behaviors toward a friend in this situation are in fact more probable than aggression.”

However, experiencing “rejection for someone else” may evoke more negative feelings and aggression in close relationships than “rejection with no reason.”

The study said: “Knowing that others are more preferred is a ‘sting’ leading to aggressive tendencies even against the befriended rejecter.”

The user in the Mumsnet post said she and her ex dated in high school 10 years ago. They had a “very messy” breakup, but “the whole thing seems like a lifetime ago to me and I have long since moved on with my life.”

The user said she “felt very hurt” and “came to the conclusion that her friendship with me is not a priority to her anymore” and that she should “accept it and move on.”

Others told her she should speak to her friend, but the user said: “I don’t want to ruin her 30th and I also don’t know if there’s anything that she can say that will fix this for me.”

Several users on Mumsnet came to the defense of the original poster.

User milesmachine said: “Wow, this is utter madness and YANBU to feel hurt and betrayed.”

NameChangex3 wrote: “She obviously does not value the friendship as you do. And surely she knows how sh**ty she’s being. She’s playing dumb.”

User oopsfellover said: “Your friend is being an idiot, and will probably realize this soon enough. Asking you to arrive and leave at certain times is ridiculous - if your ex has a problem he doesn’t need to attend and nobody else needs to overthink this…”

Some users said that there may be something else going on behind the scenes and that the original poster may not be aware of them.

User GreenManalishi said: “There’s more to this that you’re not aware of. Maybe her partner feels some allegiance to your ex and is pulling rank. Whatever the reason, this is sh**ty of her, I’m sorry.”

MichelleScarn said: “It’s absolutely madness! I’d be thinking [this] must be a smoke screen for something else going on!”

User FizzyTango suggested: “I wonder if she is closer to your ex than she is letting on. Or she sees that your ex and his new partner would be a good fit to socialise with in future and she doesn’t want to burn that bridge….I would be really hurt in your situation too…”

Newsweek was not able to verify the details of this case.