Bestfriend help please?

Ok so my bestfriend & I have grown up together & never gotten in a big fight until now. I had been talking to the boy for about two months so my bestfriend Genna planned a "date" sorta for us all to hang out so she could be my wing man but instead she ended up throwing herself on him flirting every chance she got all day! She acted like a total slut. But after about a week of talking it out & her promising not to talk to him even though he liked her & deleting his number (her own choice) we made up because I knew she was genuinely sorry. Then the other day we were hanging out & I went through her phone & found out she had his number under a fake name & had been texting him flirting for days! When I confronted her about her she said she didn't want to hurt me & they were just friends. I knew she was lying they were talking so dirty! We haven't talked for a few days & she called me earlier apologizing but I just kinda told her I didn't know. Any advice on what I should do?