A question posted to Reddit’s r/AmItheAsshole forum in early 2020 still circulates in group chats and relationship advice corners of the internet years later: a teenage girl admitted she had a three-year crush on her best friend’s ex-boyfriend’s brother and wanted to know if acting on it made her a bad friend. By March 2026, the post has resurfaced again, reigniting a debate that never really settled. Who gets to decide which people are off-limits after a breakup, and does flirting with an ex’s sibling ever end well for anyone involved?
The original poster, who went by the username Feb on Reddit, described a situation many people recognize but few talk about honestly. She liked a boy named Jacob. Jacob happened to be the brother of her best friend’s ex. She had been interested in him long before the breakup, but the timing made everything feel loaded. Commenters in the original AITA thread split sharply: some said feelings don’t follow friendship rules, while others argued that pursuing Jacob would signal to her best friend that loyalty had an expiration date.
That tension sits at the center of a broader pattern playing out across social media, where overlapping friend groups, post-breakup boundaries, and the temptation of “revenge romance” collide in ways that rarely resolve cleanly.
How Friend Groups Get Tangled With Exes and Siblings
When a romantic partner enters a tight friend circle, the breakup almost never removes them completely. Shared routines, group chats, and mutual friendships create a web that one split cannot untangle overnight. Dr. Miriam Kirmayer, a clinical psychologist who specializes in friendship and social connection, has noted in interviews that post-breakup friend group dynamics are one of the most common sources of social stress her clients describe. The person who introduced the partner often feels a sense of ownership over the group, while the partner who stayed embedded feels entitled to relationships they built independently.
Siblings add another layer. In a Facebook discussion about whether it is acceptable for a sibling to maintain a friendship with someone’s ex, responses ranged from calling it “a betrayal of the highest order” to insisting that adults cannot police their relatives’ social lives. The divide tends to fall along a predictable line: people who have been recently hurt lean toward strict boundaries, while those with more distance from a breakup are more likely to see nuance.
Research supports the idea that these feelings are not just drama. A 2016 study published in the journal Personal Relationships found that contact with an ex’s social network after a breakup was associated with greater difficulty adjusting emotionally, particularly when that contact was involuntary or felt unavoidable. When the contact involves a sibling who is now flirting, the emotional stakes climb even higher.
The Specific Dilemma: When the Ex’s Brother Starts Flirting
Feb’s Reddit post resonated because it captured a moment many people face privately but rarely discuss openly. She was not scheming. She had liked Jacob for years. But the breakup reframed her crush as a potential act of disloyalty, and she knew it.
The complication intensifies when the sibling is the one initiating. In a separate and more dramatic case compiled in a Best of Redditor Updates thread, a woman described “seducing” her ex’s older brother after a painful breakup. Commenters overwhelmingly warned her that both brothers were problematic, with one described as controlling and the other as manipulative, and that the entire dynamic seemed engineered to create conflict rather than connection.
Licensed marriage and family therapist Vienna Pharaon, author of The Origins of You, has written extensively about how people sometimes pursue relationships not because of genuine attraction but because the relationship serves an emotional function: validation, revenge, or a way to stay connected to someone they have not fully let go of. When a woman is “tempted to flirt back as payback,” as the recurring version of this scenario describes, the motivation is not romance. It is retaliation wearing romance as a costume.
Revenge Romance: Satisfying Fantasy or Slow-Burn Disaster
The fantasy is straightforward. You flirt with the brother. The ex finds out. They feel a fraction of the hurt they caused. Justice is served. But the reality, according to both therapists and the people who have lived through it, almost never follows that script.
A BuzzFeed collection of petty revenge stories between former friends illustrates the pattern. Contributors described tactics that felt satisfying in the moment: subtle provocations, strategic social media posts, calculated silences. But many of the same storytellers admitted that the most effective “revenge” turned out to be simply walking away. The petty moves kept the conflict alive. Disengagement killed it.
Psychologist Dr. Ramani Durvasula, known for her work on narcissism and toxic relationship dynamics, has cautioned in her YouTube lectures that revenge-motivated romantic choices tend to backfire because they keep the person emotionally tethered to the very situation they want to escape. Instead of moving forward, they are making decisions that are still defined by the person who hurt them.
In the context of the ex’s brother scenario, flirting back does not just risk the friendship. It risks creating a new entanglement that is rooted in resentment rather than genuine interest, which is a shaky foundation for anything lasting.
How Online Communities Weigh Loyalty, Autonomy, and Petty Payback
The internet is not of one mind on this. In a Facebook group discussion asking women directly whether they would date an ex’s brother, the responses covered the full spectrum. Some argued that a good man should not be disqualified because of his sibling’s behavior. Others said the emotional baggage and inevitable awkwardness made it a losing proposition regardless of how decent the brother might be.
What stands out across these discussions is that the people who have actually done it, dated an ex’s sibling or a friend’s ex’s relative, rarely describe it as uncomplicated. Even when the relationship itself was healthy, the surrounding social dynamics created friction that required constant management. Holiday gatherings, mutual friends, and the simple act of posting a photo together all became potential flashpoints.
The “girl code” and “bro code” frameworks that dominate these conversations online are blunt instruments. They treat relationships as territory and people as property. But dismissing them entirely ignores something real: when a close friend feels betrayed, the emotional damage is genuine whether or not the betrayal was technically justified. The question is not whether you have the “right” to date someone. You do. The question is whether the relationship is worth the cost, and whether you are pursuing it for the right reasons.
What Healthy Boundaries Look Like When Everyone Is Intertwined
Therapists who work with young adults on friendship and dating conflicts tend to offer the same core advice: clarity beats secrecy, and honesty beats strategy.
If the attraction to the ex’s brother is genuine and not motivated by payback, the first conversation should be with the best friend, not with the brother. That conversation will be uncomfortable. It may end the friendship. But pursuing something in secret almost guarantees a worse outcome. A Reddit thread about a secret hookup between friends that eventually became public showed how secrecy and shame corroded the relationship far more than the hookup itself. The demand to “forget it ever happened” only deepened the damage.
For the woman in the recurring version of this scenario, the practical steps are less dramatic than the internet makes them sound:
- Name the motivation honestly. Is this about the brother, or about the ex? If removing the ex from the equation would also remove the interest, that is a clear signal.
- Talk to the friend first. Not to ask permission, but to give them the respect of hearing it directly rather than through the grapevine.
- Accept that the friendship may not survive. That is a real cost, and pretending otherwise is not fair to anyone.
- Do not treat another person as a weapon. The brother is a person, not a chess piece. Using him to hurt an ex reduces everyone involved.
None of this is simple. But the stories that circulate online, from Feb’s earnest AITA post to the more explosive revenge sagas, all point toward the same conclusion: the relationships that survive these tangles are the ones where people chose honesty over tactics, even when tactics felt more satisfying in the moment.
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