AITAH for ruining my sisters marriage?

A 20-year-old woman shared her perspective on a complicated family situation involving her sister Sarah (30) and Sarah’s husband Frank (28). Despite a rocky marriage, Sarah and Frank had stayed together for four years, though there were constant public arguments. Over time, the woman and Frank became friends, and she developed feelings for Frank’s best friend, Lucas. When Sarah found out, she became controlling and tried to interfere in her life.

After Sarah abruptly moved out of her home, she began showing interest in another man, Henry, while still married. The woman eventually reconnected with Frank to check on him, which led to Sarah and Frank arguing, ultimately ending their marriage. Sarah now blames her for the breakup. Is the woman wrong for her role in the situation? Read the full story below.

‘ AITAH for ruining my sisters marriage?’

I (20F) have a sister Sarah (30F), my relationship with her has always been complicated. Despite our ups and downs, I love her very much and want the best for her. She has been married to her husband, Frank (28M), for four years. Their relationship moved fast—they got married within eight months. While my family is very religious, Frank’s isn’t, so they had a courthouse wedding followed by a small family dinner.

Their relationship has always been rocky. They argue openly at family gatherings and often involve others in their fights, which makes events uncomfortable for everyone. Because of this, I initially had a tough time getting along with Frank. However, over time, we became friends, bonding over shared interests and frustrations about Sarah’s behavior.

About a year ago, I started visiting Frank more frequently because I developed feelings for his best friend, Lucas (25M), and used those visits as an excuse to spend time with Lucas and talk about my feelings. However, Sarah didn’t like the idea of me and Lucas potentially being together. She actively caused tension over the situation and even started fights with our entire family about him. Sarah also has a habit of making every decision I make—no matter how unrelated—sound like it was influenced by Lucas.

For context, I work full-time and attend university at night. In Brazil, it’s not as common to live on campus, and my university doesn’t offer that option. I currently live with my parents but have plans to move in with Lucas in March. He is living in another state due to work, and I need a couple more months to prepare financially for the move.

Seven months ago, Sarah abruptly moved back into our parents’ house, saying she needed space to think. She didn’t tell Frank beforehand and simply left while he was at work. Out of respect for her, I cut off all contact with Frank, even though we had become good friends.

During this time, Sarah shared that she was dealing with a lot of complicated psychological issues. I tried to be understanding, but her behavior toward me became controlling. She demanded I share my location with the family 24/7, stopped me from going out, and would randomly show up at my university to check on me. She even took photos of my messy room and shared them in the family group chat to shame me.

Meanwhile, she started talking about a man from her church, Henry (40M), who is divorced with a young son. She often asked me and my brother, Mark (34M), if we thought Henry would make a good husband or if she’d be a good stepmom. I told her that it was disrespectful to Frank to entertain these thoughts while still married, but she insisted that she was no longer married.

Two weeks ago, she threw Frank a birthday party. I didn’t attend, but during the party, Sarah disappeared for several hours and didn’t answer any of Frank’s texts or calls. When she eventually returned, she had an argument with Lucas and made hurtful comments about me, which caused tension between me and Lucas. At this point, I was fed up with her behavior and decided to reconnect with Frank.

Last week, I visited Frank to check on him and discuss holiday plans. During our conversation, he mentioned Sarah had attended a church event at a man’s house and asked if I knew whose house it was. I guessed it might have been Henry’s. This upset Frank, and he called my brother, Mark, for advice. Mark calmed him down and suggested they talk things out.

Frank later confronted Sarah about the event, but she denied everything. The confrontation escalated, and after another big argument, she officially ended their marriage and moved back into our parents’ house.

Now, Sarah is blaming me for their breakup, saying I caused the fight by reconnecting with Frank and mentioning Henry. She’s also trying to turn our family against me, but Mark is defending me because he witnessed much of what happened. Unfortunately, my parents are siding with her, and she’s furious with me. I feel like she’s projecting her issues onto me, but the way my family is treating me has made me question if I’m at fault. AITA?

Here’s the feedback from the Reddit community:

gumballbubbles −  This is really hard to follow.

Known_Two_2072 −  Lol why not just make up a fake name for this fake story bro.

No_Use_9124 −  NTA You genuinely didn’t do a thing to cause their break up. This is all abt them. Stand up and just say, “Absolutely not. I am not responsible for your marriage not going well.” And ignore them all until they get over it.

FrostyVibessss −  You are NTA for your sister’s breakup. While you reconnected with F and mentioned H, it was ultimately your sister’s actions and choices that led to the end of her marriage.

MamaWelder −  NTA but stop being involved, it’s getting real weird in here.

Petulantraven −  Wait, so your sister left her husband and moved back in with your parents. Then she romanced a guy. Her husband asked if you knew anything and you shared what you knew. Now your sister is blaming you that her husband knows what she’s done?. NTA. Definitely not the a**hole. Your sister is very selfish. You don’t get to have your cake and eat it too.

atmasabr −  Now she’s blaming me for their breakup, claiming I caused the fight by telling him lies that would ruing their relationship.

I’m not sure it’s particularly wise for everyone in your family to be up your sister’s b**t and for her to actually entertain any family discussion about who she fraternizes with, but since that is your family dynamic, it is hypocritical for her to expect you to show a level of discretion shown by no one else, including herself.

She has said directly within the family that she is not married. No reasonable person would believe it decent for her not to share that same sentiment to her husband.  I’m being treated like the villain for reconnecting with F, but I feel like she’s projecting her issues onto me. You have called the matter correctly. Your sister was caught in the web of her own lies. NTA.

Dry_Ask5493 −  NTA. What took from this is that your religion and family are toxic and you should be working to get free from all of it. Stay away from men that are too old for you and cut off your delusional toxic sister.

SurroundMiserable262 −  ESH. You knew what you were doing telling him…but she also said her marriage was over and effectively playing one off against the other. Tipping her toe into setting up a life with him whilst not fulling letting go of her husbamd. What you said was the straw that broke the camel’s back. But you did place that straw on so yeah you’re going to get the blame for it. Honestly it depends how much you care. If it gets tough a home see if you can move in with F or your brother. 

AnGof1497 −  NTA. Sister is m**ipulative and real piece of work. Watch your back OP she’ll come for you and attempt to destroy your future relationship(s).