 It's a pretty long story but I'll post a TLDR on the end of my text. Also please excuse grammar and writing, English is not my first language. 

This whole subject started some months ago between me and two of my friends. Let's call them H and F. My friendship to F began because we were roomies and she kind of introduced me to H. Me and H realized over the time that we share a lot of interest, like languages and traveling, sports etc. So we spend most of our free time and also university time together. We wanted to learn new languages like Arabic and French and these are offered at our uni. We always asked F, if she wants to participate or wanted to do something different but she always declined. Then we got the opportunity to study for some time abroad and again F said that she isn't interested in that sort of stuff. I'll come back to that later.. More and more she excludes herself from activities in our group (also with others) and spends more time with her bf, which was okay for us all the time. But she always started arguments about how much we exclude her from our friendship and she feels sad. H and me always tried our best to do other things with her but she used to get pissed when we also talked about our share interests and behaved like we weren't allowed to pursue our hobbies, if she doesn't like them. It escalated when we planned a holiday with our three bfs for next year. When we wanted to start booking F said she doesn't want to go, because she rather wants to go to Japan with her boyfriend alone and needs the money and vacation days for that. Okay for us, but later I told her that I met with the others to plan our vacation she suddenly blocked me and ignored me at school. Her boyfriend told me that she feels excluded again and needs time for herself  to be alone for a while. H and me didn't really understand what was going on because she didn't want to go with us and now ignored us and even ran away when we got close to her, so we left her alone and didn't talk to her anymore. Some days later she texts me that I am the worst friend ever and should have known that she needs me although she didn't show it and we should have asked her about our aktivities like the languages and the vacation more often. I'm sorry but how am I supposed to know that I can't read minds?

TLDR
My friend accuses me of excluding her and leaving her alone when she needed me the most, although she ignored me and told her boyfriend she needed time to be by herself. 