I was lied to by my bestfriend and now she is playing thr victim...

My bestfriend and I have been friends for approximately 3 years and we became really close over the years. Recently, we went out for her birthday and she invited some of ber other friends who were male. At the time, I was having a hard time and one of her male friends took an interest in me. She took the initiative and set us up together. We've been dating a little over three months and everything has been really great. Us three had grown tremendously close to the point where we were all best friends. About a month ago, my boyfriend and I had an arguement which caused a little notch in our relationship and it was taking a toll on me. Since my best friend was close to both him and I, I asked for her help and I asked that she talked to him and understand his situation since he founf it really difficult to talk to me about it. I never had a problem with them speaking as I trusted them whole-heartedly and I knew they wouldn't do anything wrong. They spent over an hour on the call with him explaining why he has been off lately. She tried her best to understand since the situation was very personal to him and our relationship. He just wanted some advicd on what to do so he vented to her. I knew about the interraction and had no negative feeling about it because I wanted him to have a platform to vent and be understood. Even thought I wanted him to come to me and tell me, I still thought it was okay. After he vented to her about te situation, she called me and told me what he said, but an exaggerated version that tore my heart and had me in tears. I cried all night to her on the phone and in school the next day. Keep in mind that, while I cried to her in the night, I asked her if it was wise to speak to him about it. All she said was "He just came back from football and he's tired so he'll talk tomorrow". So I left it alone and cried. The following day I was a wreck at school. I met my best friend in the morning and people did look at me weirdly but I could have cared less. I told only one other friend of my situation and it was someone I could trust. The rest of the day was a drag until I returned home from School. My best friend messaged me saying that she was dissappointed in my behaviour at school (crying) and that some people called me 'desperate'. I apologised for my behaviour but I questioned her about how did other people know of my situation to call me desperate. I asked her if she had told anyone of the call and the details, she swore that she didn't. I never accused her but she claimed that I did. Later, I found out that she had spread all the information about my private life with my boyfriend to a few people in school after claiming she didn't. After that, she blocked me on all social media platforms and is now playing the victim. My boyfriend, who I have now spoken to and came to an agreement with, is also angry at her for spreading details abd personal information of the call and also asked her about it. He too, was blocked and removed. (On a side note: Her boyfriend also broke up with her one month before my boyfriend and I began dating. It has crossed my mind sometimes that she did want me happy, but at times her breakup trauma, gets het jealous of my relationship. Also, during her break up, she would have vented to my boyfriend and I as well as posted on social media; publicising her breakup even though we advised her otherwise.) Who was at fault in this case? Is she by any means right to 'play the victim and block us out'? What do I do because even though my boyfriend and I are on better terms, I still miss her but she is stubborn and would not accept her wrong?