I suspected that might be the case with her boyfriend. I'm not sure why (maybe just from my own experience), but I got the sense that she had trouble with her relationship beyond just distance. There could be a lot of things happening - normal relationship drama, her realizing she doesn't want to be with him, him pulling away from her, I don't know what's going on for you friend, but she's probably as confused as you are with all this.

It's totally ok to pull back if you feel like this is hurting you or too much to deal with. Whatever is happening, it's not your fault. At some point the burden is on her to figure out what she wants and needs, but if I had to go with my gut (again, going off similarities to things I've been through) I'd say it'll take a while for that to happen. Make sure to take care of yourself too! And best of luck.