Was this wrong of him AND her to do this to me? What do i do?

Okay, so a couple weeks ago, my boyfriend dumped me over text and in the same week, he started going out with my best friend. Now, my best friend told me she would never ever like him and that she would never do something like that to me. But, the thing is, neither of them ever even told me they were going out. And both of them acted like they didn't do anything wrong and they both started ignoring me and not even talking to me and started spreading rumors that weren't even true. A week later, my ex started texting me saying that all of what was happening was all of my fault, even though i wasn't even talking to them or anything, i was just minding my own business. And then she said she was sorry, but got mad at ME for "getting in the way". I swear i hadn't done anything to them to make them do this to me, i wasn't saying anything to anyone...was this wrong of them to do? My other friends are saying that i shouldn't be friends with her anymore, because right now, me and her are actually speaking now...oh, by the way, she knew i still liked him and still like him and still went out with him