AITA for not choosing my sister when she split with her partner?

A Reddit user (18M) shares their story of navigating a tricky family situation after their older sister (28F) broke up with her partner (23M). Despite the breakup, the user chose to maintain a friendship with the ex-boyfriend, who had become a regular in their Dungeons & Dragons group. The decision strained their relationship with their sister, especially after discovering she had cheated on her ex, a fact she admitted but felt unfairly judged for. Now, the sister has decided to distance herself, accusing the user of favoring her ex over her.

‘ AITA for not choosing my sister when she split with her partner?’

I (18M) have an older sister (28F). We only recently started to become close (past 4 years or so). Around two(?) years ago, she met this guy (23M). He made a great impression on me when we met the first two times. I thought they were a great match! They made each other happy, and I got to see my sister more than I had in a long time, which made me happy too.

I’d invited them to Dungeons & Dragons at my place, because they both seemed interested. They both agreed. Due to the ten year age gap between my sister and I, I was happy that we could finally find a hobby to mutually enjoy. However, 6 months ago I noticed that things were off.

They would come over looking stressed and dejected, and sometimes it would seem like my sister would text Boyfriend and he would deflate. I didn’t want to bring it up because, again, not really my business. But it began to get to a point where everyone at the table could see the conflict (which wasn’t hidden very well, but I thought I may just be over-analyzing things).

So at some point, I go over to their apartment. My sister wasn’t there, but me and her partner had hung out together plenty before so I wasn’t bothered. After we chilled for an hour or two, I finally asked him what was going on. I told him he didn’t have to tell me anything, that it wasn’t my problem and if he was uncomfortable then I’d leave it be and forget it.

But to my surprise, he was very open. He told me that my sister had cheated on him (emotionally and physically) with more than 3 other men, then tried to blame it on her mental health or suddenly being polyamorous. He expressed to me how I should ask her for her side as well.

I told him I’d like proof to confirm the accusations. There was more than enough. The rest of the hangout went by without any issues. The ex boyfriend still comes to d&d, and we have a great time! We talk often, and have a normal friendship.

I’d never asked for my sister’s side because she was very unstable at the time, and I was scared that she would blow up on me. We had a conversation where I told her I didn’t not want to fight or argue with her, and that I still loved her unconditionally. I told her that while, yes, my perspective had changed, that didn’t lessen my love for her.

She explained to me that she felt like their intimacy had gotten stale (which was none of my business to begin with, and I did not press her for information about that). And said that she was “intimidated” to speak with him about it because nothing changed when she did. I could understand both points, because he worked long shifts nearly every day.

She told me that she felt like I was “enjoying” her ex boyfriend more than her. I told her that I would not lie to her, and that I would continue hanging out with said ex. She then told me that she would be distancing herself from me while he was still in my life.

See what others had to share with OP:

TrickSea_239 −  NTA. Doesn’t sound like you “didn’t choose your sister”. That implies you cut her out, but from the sound of it she’s the one cutting you out.

She’s the one that cheated. You’ve seen the evidence. I’d say her ex was more entitled to support than she is, regardless. If he finds this support through the D&D group, then it’s nice of you to let him carry on coming round. If he works long hours, he probably looks forward to this interaction. Your sister can get her interaction in the various men she’s sleeping with.. Sounds like a tame FAFO to me.

Fragrant_Rope403 −  NTA. You handled that quite maturely for an 18yo. She will come around.

Corfe-Castle −  NTA. Sis was cheating because she was bored of the intimacy. The ex didn’t cheat and you have things in common I’m guessing she’s feeling isolated and guilty seeing you both hang out.

P35HighPower −  The most interesting thing about this is that being the youngest at 18 you are the one acting in the most mature manner.. Well done and no, NTA.

SheepPup −  NTA. I wanna rephrase this whole thing more succinctly “my sister is mad that I didn’t stop talking to her boyfriend, who is my friend, after she cheated on him. Am I the a**hole?” No. No you are not.

KindBoysenberry7333 −  NTA that being said I have seen first hand familiar relationships go up in flames by people choosing to still be friends with their family’s exes. So while you are allowed to be friends with whoever you want I would recommend thinking about potential consequences and whether or not you are willing to live with them. Again NTA but it is defiantly something to consider.

YearOneTeach −  NAH. If you want to be friends with him you can, but you also have to accept that it’s completely fair for your sister to distance herself from you as a result. Most people do not want to remain that close to their exes, and if you are remaining friends with him and involving him in D&D it makes sense that she would want to take a step back and no longer be a part of those things.

I’m kind of curious why you haven’t asked for her side, or at the very least tried to talk to her about the underlying issues. It kind of seems like you know she’s struggling mentally. Do you know if she has sought help? Is she in therapy?

Mrs_Gracie2001 −  You never asked her? How do you know you got the whole story?

LibraryMegan −  NAH It’s definitely weird to keep hanging out with your sister’s ex after they broke up, regardless of how they broke up. You have to decide which relationship is more important to you, because she is distancing you over it.

wwydinthismess −  NTA, but she has to move on from her past so she can heal and hopefully be a better partner in the future. It’s reasonable she never wants to think about that relationship again. So as long as you remain friends, it’s reasonable she needs to distance herself. It’s a fair boundary. It doesn’t sound like she’s mad, and he didn’t hurt her so there’s no reason to have to “take her side”. This is just a natural consequence of these things.