AITA for cutting ties with my sister after she destroyed my life?

I (32F) have always been close to my sister Emily (28F). Growing up, we were inseparable. Our bond was strong, and we shared everything—our secrets, our dreams, and even our heartbreaks. Despite our age gap, we understood each other in ways that no one else did. I was the more responsible, reserved one, while Emily was the carefree, outgoing sister. She was always the center of attention, and I had no problem with it. I loved seeing her shine and often found myself cheering her on from the sidelines.

As we grew older, our lives started to take different paths. I focused on my career and settled into a steady relationship with my fiancé, Michael (35M). We met through work, and it didn’t take long before we became inseparable. Michael was everything I had ever wanted—smart, caring, and incredibly supportive. After three years of dating, he proposed to me, and I was overjoyed. I had never been more certain of my future. The engagement felt like the next chapter in my life, and I couldn’t wait to marry the love of my life.

But that’s when everything started to unravel.

At first, there were small signs that something was off. Emily and Michael always got along well, and I didn’t think much of it when they would chat for hours over the phone. Michael often talked about how much he admired Emily’s confidence and sense of adventure. I thought it was just harmless admiration, nothing to worry about. But when Michael and I were planning our wedding, I began noticing that Emily seemed to be spending more and more time with him. They would text late at night, and when I asked Michael about it, he would assure me that it was nothing. I trusted him, so I let it slide.

However, things began to escalate.

About a month before our wedding, I was cleaning up our apartment when I found a series of text messages on Michael’s phone. The messages were between him and Emily. At first, I thought it was just harmless flirting, but as I read more, it became clear that something much deeper was going on. They were talking about how much they enjoyed spending time together, and how much they were "starting to feel something more." My stomach dropped as I read, and I could feel my heart shattering. I confronted Michael immediately, and after a long, painful silence, he admitted that he had been having an emotional affair with my sister for months.

My world came crashing down. I felt betrayed in every way possible. The two people I loved the most, the ones I trusted above anyone else, had been lying to me behind my back. I was devastated. I immediately called Emily, asking her to come over. When she arrived, I demanded an explanation. She didn’t even seem shocked that I knew. She confessed that she had developed feelings for Michael over time and that it was never planned, but it happened. She said she loved him, and that they had been spending time together alone, away from me, because she didn’t want to hurt me.

At that moment, my entire world shifted. I couldn’t breathe. My sister, the person who was supposed to be my best friend, had betrayed me in the most unimaginable way. She had stolen the love of my life, and the worst part was that she didn’t seem to regret it. She cried and begged for my forgiveness, but I couldn’t even look at her.

I ended things with Michael immediately. I didn’t care that we had spent years together. I didn’t care about the wedding we had planned. I walked away from him without a second thought. The betrayal was too deep, and I knew I couldn’t be with someone who would so easily destroy our relationship.

But it wasn’t just Michael I had to walk away from.

I couldn’t bring myself to speak to Emily for weeks. She kept texting me, calling me, and even showing up at my house unannounced, but I couldn’t bring myself to forgive her. Every time I saw her face, I saw the person who had hurt me the most. She was my sister, but in that moment, she felt like a stranger. She had destroyed everything that mattered to me—my trust in her, my relationship, and the future I had envisioned with Michael.

My friends and family tried to convince me to talk to her. They said that Emily was just confused, that I needed to forgive her and move on. But I couldn’t. I couldn’t forget what she had done. I felt like my entire life had been a lie. Emily’s actions had completely shattered my sense of security, and I was afraid that if I forgave her, she would hurt me again.

Finally, after months of silence, I decided that I needed to cut ties with her for good. I blocked her on social media, stopped answering her calls, and refused to meet with her. I sent her one final message telling her that I couldn’t have her in my life anymore, not after everything she had done. It felt like a weight was lifted off my shoulders, but at the same time, I felt guilty. Emily was my sister, and no matter what had happened, I should have been there for her. But how could I ever forgive someone who had caused me so much pain?

In the weeks that followed, I found myself questioning my decision. Had I been too harsh? Couldn’t I have at least tried to repair our relationship? My friends were divided. Some told me I was right to walk away and protect myself from more hurt. Others said that family was everything, and that I should have tried to find a way to move past the betrayal.

My family was also divided. My parents didn’t understand why I couldn’t forgive Emily. They thought I was being too harsh and that I was ruining our family. They tried to make me see reason, but I couldn’t. I couldn’t allow myself to be the person who let someone so toxic back into my life.

Now, it’s been over a year since the betrayal. Emily and Michael are together, and they’re happy. I heard through mutual friends that they got engaged, and I felt a mix of anger, betrayal, and sadness. I wasn’t invited to their wedding, and I don’t know if I ever will be. But at the same time, I’ve come to realize that I don’t need them. I’ve rebuilt my life. I’ve found new love, and I’ve learned how to trust again, but I’ll never forget what they did to me.

So, AITA for cutting ties with my sister after she destroyed my life? Could I have tried to make things right with her, or was walking away the best choice?