Ok so supposedly she knows you talk to your ex.
Then there is no reason for her to flip out.
Unless she was looking for one to make you look like a bad guy when she leaves you and to justify why she left you. (Because you were a "bad guy")
Unless this is not the full and true story, which I’m sure it’s not because this is your side.
There is always 3 sides to a story, her side, his side and the truth.
Maybe there's no peace in this world, for us or for anyone else, I do not know. But I do know that, as long as we live, we must remain true to ourselves.