[24F][23F][24M] Don’t Know If I Should Cut Off A Long Time Friend?

I used to have a very close friend group in college, two of those people from the group being my best friend and a very close guy friend of mine. Let’s call guy friend Greg.

Greg always had a giant crush on BFF but after on and off dates BFF decided she doesn’t see him that way. However, sometimes when we would all go out she would get jealous of him paying attention to other girls, so sometimes she’d flirt and kiss him to keep him pining. Dumb college drama.

One night I’d didn’t go out with them and they ended up going back to his place and spending the night. I thought it was scandalous as she always said she just didn’t see him that way, but with the flirting and leading on involved I could see her developing feelings or feeling a connection at some point. She was really embarrassed about the whole situation and although she hooked up with him in the morning after while she was sober, she said she didn’t remember anything that happened the night before and was concerned about it.

I was so so stupid at the time and assumed she was just embarrassed about the whole thing so she just didn’t wanna talk about it with anyone anymore. Months later the friend group started to fall apart and she didn’t want to speak to Greg at all as it was too painful for her to try to go back to being friends after what happened. Again, I just thought she was ashamed that she crossed the line and gave him the wrong idea and in that ruined the friendship.

Recently, she came to me and told me that she was scared he took advantage of her while she was drunk. In the morning she asked him what happened and he laughed and said he didn’t remember. She asked if a condom had been used (she was a virgin at the time) and if she needed to get a Plan B, and he said he didn’t remember but didn’t think they had sex. Ever since that night she has been traumatized and betrayed by her friend who took her home and hooked up with her when she wasn’t in her right mind.

I feel so awful for her that this has haunted her since. I am still friends with them separately, but since she is my best friend I feel this obligation to cut him off from my life. I haven’t told him that I was doing this or why, so I’ve just been really distant but he keeps making plans to want to hang out again to catch up. My heart is in a weird place and I don’t know how to address this situation. Can someone please give me insight on what you would do here?