I (18M) am part of a small friend group consisting of me, my girlfriend (E), best friend (R), and a girl I'll call L. Last year, L got a boyfriend (B) who is a first-year at a nearby college. For reference, we're all seniors. We were all extremely happy for her, obviously, because her last boyfriend was neglectful and led her on for almost two years. Everything was completely fine until about five months ago--L came to us complaining that B had forced her to stop wearing fake eyelashes. None of us thought anything of it, but it was definitely weird in retrospect.

About a month later, we all noticed changes in L's behavior. She stopped hanging out with us as much, would take ages to answer texts, and just become much colder overall. Again, none of us said anything. We just assumed she was spending more time with B. She would occasionally complain about him to us, but he rarely came up in conversation, and when he did it was almost always in a negative light.

Fast forward to last week, L tells me and E that she won't be going on our annual beach trip. No problem, but then she explained that B was refusing to let her go because he wasn't comfortable with it. We offered to let him come, but he said no because his parents wouldn't let him (grown man by the way). I made a joke at the time, teasingly asking her if that was why she hadn't been hanging out with us as much.

A day later, I get a text from E saying that I was actually right, and L had confessed B wasn't allowing her to hang out with us because B didn't trust R around her. Keep in mind, B has hung out with us multiple times by this point, and has seen them interact completely normally. R later told us that he's never had any interest in L other than a platonic friendship. During lunch, we approached L about it, who confirmed everything. She said she wasn't happy about it, but she saw B's perspective and wanted him to be happy. That's when I said something I probably shouldn't have.

I told her B was controlling her, bringing up every instance I could remember of him telling her she couldn't do or wear something. I called him abusive (which is where I think I could be the AH), and E and R agreed with me. L ALSO agreed at the time, which makes the next part weirder.

Two days later, me, E, and R got a long text from L explaining, in short, that what we said was incredibly hurtful to B, and she could no longer be friends with us if we weren't going to support their relationship. She said even if we tried to change our behavior, there was no fixing this and it was absolutely necessary to cut us off. Among other things, she called us toxic, negative, and said we have no idea how much he's done for her. I'm sure he's been great in some areas, but the fact remains that he's isolating her from her friends and controlling her life.

R tried to reach out with an apology, but she responded with a similar text to the first, reiterating that our friendship was over and there was nothing that could be done to fix it. She was more hurtful this time, claiming R couldn't understand because he's never been in a real relationship.

We've been cut off completely since then, and L avoids all of us in school. E and R stand behind what I said, but they think I should've been nicer about it. In my opinion, I think putting it as bluntly as possible was better, to show how serious B's behavior actually is. I'm really worried that the controlling behavior will become something worse, but I know that's a jump.

Was i wrong? If I was, what should I do next?

Here's a few other instances of odd behavior she told us about, to get a better grasp on B:
1. Despite L being an extremely successful student, B asks that she ignore any other colleges and go to his college with him
2. B constantly compares himself to other men--especially R and myself--even asking R if he could take L's ex in a fight
3. L said B couldn't beat a guy we know in a fight. He went to the gym and claimed he almost tore his bicep BECAUSE OF HER
4. He's made odd comments in front of myself and E about victims of abuse, pointing out their clothes and such