AIO for breaking up with my gf because of her friends

During freshman year of college, I (19M) met L (19F) at a party. She was gorgeous and kind, and we hit it off right away. There were only a few weeks left in the school year, and though we lived on opposite coasts, we decided to be exclusive over the summer. We stayed in touch, and by the time sophomore year started, we were excited to be back together. Things felt real. We officially started dating a month in, and for a while, everything was great.

But being official meant more time with her two best friends, B and D—and that’s where things unraveled.

B was chaotic and constantly pulling L into drama. L, being sweet and selfless, always dropped everything to help her, even when it hurt her—like the time B asked her to stay over the night before a big final, and L bombed the test. I voiced concern once, but L didn’t want to talk about it, so I backed off.

B’s behavior with me got weirder. She asked me insane questions in front of people—about my dick size, if I loved L, ranking girls by who I’d sleep with. I told her calmly that it made me uncomfortable. She apologized. But minutes later, she asked about a close friend I’d lost to an overdose—something she knew was painful for me. I stormed out. L called me in tears, apologizing. After that, I avoided B as much as I could.

D was a little different—more subtle but still toxic. She clearly didn’t like me dating L, always trying to come between us. I could handle the pettiness. But one night at a bar, D slapped me across the face and said, “You don’t deserve L.” She was wearing rings. It wasn’t a joke. When I told L, she didn’t believe me.

That broke me. I was tired of being disrespected by her friends while staying patient and kind. I knew L wasn’t the one hurting me, but she never stood up for me either. So the next day, I broke up with her. I didn’t tell her the real reason—I said I needed space to “figure things out.” I didn’t want to ruin her friendships, even though they were already ruining us.

Months later, L (a little tipsy) asked me what really happened, and I told her. She apologized and said she hoped I was happy. A year later, she cut B and D out of her life and found amazing new friends. By then it was too late. I never reached back out. I graduated and moved across the country. She stayed.

I still think about her all the time. I haven’t had a serious relationship since. I don’t know if I made the right choice, but I did what I felt was best at the time.

So: am I the asshole for not telling her the truth sooner? Did I overreact?