Boyfriend trouble with best friend!!

okay so I was at this party on friday night and I got back with my ex but my best friend wont talk 2 me saying "hes going to brake your heart again" and "dont c*m runnin 2 me when its over in like a week" shes being unbeliveably bitchy!! but we were going out for a year and a half we were very very close and I know were meant to be together,I said this 2 her but she wont listen how do I make her understand? I can c her point of view but she cant c mine! im in love with this guy I went on holiday with him and every thing!! please help me I want my best friend back but I also want to keep my boyfriend!

does she have a boyfriend
has she had 1
if not
use that against her
tell her that you wouldnt understand uve never had 1
if she has
then say that you miss him and
that "even though he broke my heart before,
I want to try it again with him"
u know

well she did ave a boyfriend but doesnt any more,I think she might be a little scared of losing me thats all!