my best friend likes my boyfriend?

my best friend and i liked this guy, even though she didnt know him at all. in january, he asked me out and my friend was upset. My other best friends convinced me to say yes, and my friend who also liked him said she was over him and told me to say yes, so i did. now, she told my other friends to tell me that she still likes him. i was like well then ill break up with him, but she wouldnt let me. then, she was mad at me (which makes no sense, and i was pretty angry at her. After all, she told me to say yes, then she starts being a baby and saying to my other friends how she wanted us to breakup so she could go out with him!) Today she talked to me and tried to get through that I had to either choose what to do (break up with him or not). I dont want to break up with him, and she says that she doesnt care if i don't...

So, I don't know what I'm asking. But what would you do if you were in my situation?