Backstory first: I met a group of 5 or 6 people a couple years ago. multiple serious relationships in this group.  
As I got to know them better, I eventually found interest in one of the girls in a relationship. I did nothing about it. The chemistry between us was great though, better than anyone else's in the group. The closer I got to her, the less i cared about the fact that she had a boyfriend. Him and I were not close at all, barely talked to each other. He was concerned with how close me and her were, friends informed me.

  
Fast forward a couple months after meeting them, I can start to tell that her boyfriend is kinda a shithead. I bring it up to multiple people in the group. They all tell me to just be cool, "he isn't all that bad". The more that I find out about their relationship, usually through friends in the group, the more inclined I am to tell this girl how I feel. So eventually one night, I do. She feels the same way. We talk about her leaving him and trying us, but that ended up going nowhere. I drop it all, knowing this could cause harm to our friend group.

&amp;#x200B;

A month passes, and she was giving me a ride home from a party at a friends house. Once we get to my house, she tells me she wants me. She says shes been thinking about "it" all weekend. I tell her i'm not doing anything with her if she is still with her boyfriend. She explains that its not that easy, and we talk for close to an hour. This ends up with us talking in circles, she leaves and i figure that's the end of the night. A hour or two later, i hear my doorbell. Its her. She tells me she did it, she broke up with him. So I let her in.

Laying in bed afterwards she confesses she lied. That she didn't break it off. At that point i'm surprised, but not mad at her. We talk it through, how i wont tell anyone what happened and neither will she.  


Today, months after we hooked up, the group is in a uproar. They found out that her boyfriend cheated on her. Now everyone thinks hes an asshole, they kick him out of the group. They all start ripping him apart, and pretty much shit on his life. All the meanwhile i'm sitting there knowing what she did first. 

AITA for pursing anything with her to begin with? Is she the asshole for playing innocent? Should i keep what her and I did a secret? Are they assholes for jumping ship on him, after defending him to my criticisms?   


  