<human>: My 31 year old ex has a 25 year old "best friend" who is a girl who he was having sleepovers with without telling me. These two have known each other for like six years or so and he texts her constantly. 

 I found out finally a couple of weeks ago because I called him and heard him at a restaurant with her. He admitted they were having dinner and she was sleeping over. I forgave him and he promised to stop. I forgave him because he is going through a rough time concerning some family issues.

On Monday night he sent her to my monthly comedy show that I host. This is after a week of avoiding seeing me - using sickness and his work schedule as excuses. 

He let me know ahead of time that she was coming, I told him that made me uncomfortable but he assured me I had nothing to worry about. During the last comedian's act I heard her (from all the way across the room) say that he was calling her. He had been ignoring my texts I sent to him that night, so I was really upset. I called him as soon as my show ended and he dumped me on the phone. 

Then she told me she knew I was upset about her sleeping over with him (he promised me he did not and would not confide in her about that) and that she had a "special relationship like brother and sister" which seems weird because when I first met her they both admitted they used to hook up. I think usually brothers and sisters don't do hand stuff, right?

She traveled like two hours to come to my show knowing I was upset by what she did and she was unapologetic. 

So - question: How can I begin to ground myself back into my own reality after been lied to and manipulated by someone I loved and trusted? I feel like everything I know to be true is now a lie.

Can you provide a brief overview of the text?
<bot>: My ex lied to me for months about his codependent friendship with a younger woman. How can I begin to ground myself back into my own reality after been lied to and manipulated by someone I loved and trusted?