Most Helpful Girl
... She is not breaking with me nor with her new boyfriend...
She is making a fool out of here, dear, the longer you prolong this inevitable split. You are Now in what I refer to as in a "Triangle threesome," where you are way at the top, looking down, side to s side to side, at the both of them.
Have a little chat with her and tell her that you don't want to be in a Relationship with where two is company and three is a crowd which isn't a crowd pleaser.
You cannot trust her anymore, you know that now. And in the past, which was not a blast for her neither with your own flirting and flaunting, stay single for awhile and smile.
Good luck. xx
Most Helpful Guy
Yeah, break up with her. You have good reason, on top of that mutual friends is not what should pan out your future. Just break up with her, you don't even have to really say why