Its good your no longer "friends" on Facebook. Bad enough you have to see her at work. you dont need to see her on social media to. Its hard to move past someone when they are still in your life all over the place.

I am serious... You probably dodged a giant shyt storm by her ending things and going back to her EX, You didnt do anything wrong she went back to someone that she said was/is abusive. SHE did that. Not you.