With her special day looming -- and the unique connections between all the players in her story -- the OP (aka, the "original poster") turned to Reddit's infamous AITA ("Am I the A--hole") forum to see if she was in the wrong.

Certainly her actions had devastating results, but what else could she do?

Well, that's why she wants to know: AITA for telling my sister's boyfriend to not propose to her?

She started her story by explaining the internal relationships that made this uncomfortable situation almost impossible. "I (28F) have a fraternal twin sister who is dating my fiancé’s (34M) younger brother (29M). My fiancé and I are getting married in September," she explained.

She then got into the unexpected crux of the problem, writing, "My sister has made several comments about how awful my new last name will be. She has also said similar things throughout her relationship. She told me that should could never marry her boyfriend because she just can’t have this last name."

OP explained she doesn't have to take his last name, but her sister argued "she doesn’t want to keep our maiden name, she wants to have a traditional marriage where she takes her husband’s last name."

And so, last weekend while shopping for her own honeymoon clothes with her sister, OP decided to see just how serious this was -- and with good reason. "I asked her what if her boyfriend proposed to her?" she wrote. "They’ve been dating for 3 years now and my fiancé told me that his brother was looking at engagement rings. I didn’t tell her this but simply brought it up in regular conversation since we were shopping for my honeymoon outfits and she kept saying 'I can’t wait to try on wedding dresses one day' and the like."

If asked, OP said her sister said she'd reply, "Only if you change your last name." OP said "that was really selfish of her to give an ultimatum like that to someone who loved her and wanted to marry her. She rolled her eyes at me."

OP then doubled down on her stance, saying, "seriously, would you really turn him down because of his last name?" She said her sister "firmly said, 'Yes, I just can't have that name.'" When OP asked "why she was even with him knowing it won’t lead to marriage," she said her sister replied, "I don't know," and so she dropped it.

Fast-forward to the day before OP's post. "Yesterday, her boyfriend came over to hang out with my fiancé and pulled up photos of rings to ask my opinion on which one my sister would like," she wrote. "I told him the truth. She won’t marry him. That she will say no if he asks because of his last name. He asked me if she told me this and I told him yes."

In response, OP's next statement was, "He broke up with her today." As for herself, OP added, "He didn’t tell her why but my sister knows it was because of me. Now my aunt and uncle (who raised us) are upset with me and said that it’s going to be really uncomfortable at my wedding for everyone."

"But, wouldn’t it still have been if he asked and she said no?" she asked. "Should I have just let it play out?"

While it was a complicated situation all around, the top commenter had OP's back. In a post with more than 3k upvotes, they declared, "Oof. Talk about being stuck between a rock and a hard place. I don't think there really a way to win in this scenario. Especially if he was hoping to buy the ring and propose before your wedding."

"I guess it's better for him to know that she wouldn't marry him because of his last name (damn... she's petty. And clearly doesn't love him that much) before he drops a pretty penny on a nice ring," they added. "Whether they broke up now, or when he proposed and said "no" (especially if before your wedding), your wedding would always be awkward."

"There's a rock, and a hard place, and they're both between the sisters ears," commented another. "I'd wager my kids college fund on the last name being a convenient excuse because she's waiting for a bigger fish. But then, I don't have a kid, and my cats aren't displaying any academic aptitude."

Several offered examples from their own lives of either not taking their spouse's last name, or even just coming up with a whole new name in the case they didn't care for either of them. The bottom line in all of these stories? "Did she never discuss last names with her boyfriend??" marveled one commenters. Another agreed, "There are so many ways around this issue!"

Another commenter took it a step further by saying that it's not about just the last name. "It's about disrespect. She does not accept him as a person, but like a cartoon character judging him by his last name. IDK, it could be also genuine childish idiotism, which is not better," they wrote. "I hate such statements behind person's back, he deserves to know."

To anyone arguing it was the sister's place to have this conversation, several commenters noted she just wasn't going to do it ... especially after three years. "Sister was never going to have the conversation. She was going to wait until he bought a ring, hyped himself up, potentially spends a good chunk of money just for some really special fancy proposal plan to make it special for her (maybe a vacation or very nice restaurant) and allow this man to do all of this and propose to her because he believes the woman he’s been dating the last 3 years of his life, will be the woman he dedicates the rest of his life to- just to be turned down because of a last name."

"She has wasted 3 years of this man’s life, and has now caused drama into an up coming marriage," they concluded.

But not everyone thought OP had the right to wade into this potential issue in her sister's relationship. While conceding the sister is "being pretty petty about this," one commenter emphasized, "It was absolutely not your place to just flat out tell him not to propose to her and then repeat something your sister had told you like that."

"She said that to you in confidence and you just popped out with it the second he started showing you a ring," they continued. "The right thing to do would've been to tell him he should talk to her about this and see where her head's at in regards to marriage rather than just straight up ambushing her with the ring, and then let her work the situation out for herself."

They argued that OP "made a decisive move to insert yourself into their relationship, and it resulted in the relationship ending." Another agreed, adding, "It was for them to figure out together not for a unilateral decision made in secret."

"OP failed to do the easiest solution when stuck between two people in a relationship, TELL THEM TO TALK TO EACH OTHER," wrote another Redditor. "Instead she played middle man and did a poor job of it." Still another wondered, "Why did you not let it play out? Why was your loyalty more towards you BIL than your sister? Why did you rob them of a chance to have an honest conversation about this?"

One commenter explained that it's not that simple, though, because of their interconnected relationships. "Except it's not some random guy OPs sister was dating," they wrote. "It was her BiL. Someone she is going to have to keep in her life as long as she stays married to her husband." They argued OP "did a future family member a solid by not letting him waste a ton of money and end up rejected."

One Redditor said OP should have stayed out of it because how could she know what her sister really might do. "It's possible the reality of the ring would have overcome her distaste for her bf's surname," they mused. "Did you discuss this situation with your fiancé? Did he want you to tell his brother about what your sister said?"

There were some who went in even harder. "Stir s--t in your sister's relationship if you want OP, but don't pretend to be doing it from the moral high ground," wrote one person. "You've got what you wanted - you thought your sis was weird for dating someone she didn't want to marry and you surreptitiously interfered and brought the issue to a head. You didn't manage to get out of the situation without gaining the meddler label, which tbh you deserve, your moves were inelegant."

One possible solution suggested was for OP to let her "sister know he was planning to ask her soon, and that she should talk to him about the name issue and marriage in general." At the same time, they argued the name being an issue is "immature."

"Honestly you should have let him do it and find out from her," concluded one commenter. "And she was prolly exaggerating and being dramatic anyways. Sorry, going with YTA ["you're the a--hole" --ed.] even though your sister sounds like kinda an AH ["a--hole" --ed.] in general. Don’t get involved in other peoples s--t."