AITA for telling my BIL that someone is going to punch his girlfriend one day?
The original poster (OP) recounts events following their older sister's wedding to her long-time fiancé, noting that the sister and her new husband are polyamorous, each having a separate partner. The OP had met the sister's boyfriend previously, but the brother-in-law's girlfriend, referred to as Sally, seemed overly attention-seeking during an earlier engagement party.
At the wedding reception, the OP observed Sally cornering and flirting heavily with the OP's monogamous boyfriend, despite the OP's clear disapproval when she intervened. Following this incident, the brother-in-law (BIL) texted the OP demanding an apology to Sally, arguing that flirting is part of her personality, leading the OP to question if their strong reaction was justified.
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As relationship therapist and author Nedra Glover Tawwab notes, "Boundaries are not about controlling other people; they are about taking care of ourselves. They are about clearly communicating what is okay and what is not okay with us."
The OP's swift and harsh verbal response to Sally was an immediate, albeit emotionally charged, defense of their personal boundary concerning their relationship integrity. Sally's behavior—cornering the OP's boyfriend and physically engaging in a flirtatious manner—is a clear violation of social etiquette and respect for an established relationship, regardless of Sally's personality traits. The BIL's demand for an apology frames Sally’s actions as permissible, shifting the accountability onto the person who defended their partner. This dynamic suggests a potential power imbalance where the sister’s new relationship structure is being used to excuse behavior that would be widely condemned in a purely monogamous context.
While the OP’s protective instinct was understandable given the aggressive nature of Sally's advances, using extreme profanity in a public setting like a wedding reception, even when provoked, escalates the situation unnecessarily. A more constructive approach, after firmly removing the boyfriend, would have been to address the BIL privately, confirming the sister's support for the OP's reaction, and firmly stating that boundary violations against the OP's partner will not be tolerated, irrespective of Sally's 'personality.'
THE COMMENTS SECTION WENT WILD – REDDIT HAD *A LOT* TO SAY ABOUT THIS ONE.:
Users didn’t stay quiet — they showed up in full force, mixing support with sharp criticism. From calling out bad behavior to offering real talk, the comments lit up fast.
The central conflict involves the OP's strong reaction to Sally's disrespectful boundary violation of aggressively flirting with the OP's committed boyfriend, contrasted with the BIL's insistence that the OP must apologize because this behavior is deemed acceptable as part of Sally's personality.
The reader is asked to weigh the importance of defending one's partner against public harassment versus the perceived need to maintain peace within an extended family structure, especially given differing views on acceptable social behavior at an event.