Questions: Break Up & Divorce

I and my EX have a mutual friend John. John is my best friend and its his birthday next week. He promised to my EX and her friends that he was going to invite them to a party but then I broke up with my girlfriend.

John told me that he didn't invite my EX and her friends because he didn't want to make me upset. He also told me that its totally up to me and if I want I can invite them to his birthday party and if not its totally cool. To be honest I would rather not party with my EX-girlfriend BUT its my best friend's birthday and I have a lot of respect for him. I want his birthday party to be the best one ever and if he can get lucky with one of my EX's friends good for him.

I broke up with my EX and told her I don't want to see or talk to her ever again.

What would you do if you were in my shoes? Would you invite your EX or tell your friend that its best if she doesn't come BUT its totally his choice and I'll respect it?

We broke up for seemingly other reasons, but now I feel like she made them up because she was feeling guilty. I found out through a friend that she had been cheating on me. We haven't talked since the breakup and I'm wondering if I should write her a letter telling her that I know? I don't want her to think that I care... just that I know and I'm disappointed.

We finally ended things after an off and on relationship. She said she doesn't believe me when I tell her she loves me. She didn't believe that I loved her at all because I didn't show it. Truth be told I was under so much fricken stress that I neglected her got pissed off easily and saod mean things. It just burned a hole in my heart when she said that because I would do anything in the world for her.

I didn't tear up or anything but you could see it in my face and hear it in my voice. I've always been a tough guy this was the first time she's ever seen me emotional. I feel completely emasculated.

My ex broke up with me two nights ago. I couldn't see it then, but I now realize it was because of my clingyness and jealousy, all stemming from my issues of insecurity. I feel like I pushed her too far with these issues and caused her to become less attracted to me and ultimately caused her to break things off. I'm devastated, but working on improving myself to figure out how to make sure this doesn't happen again.
I really want your insight on how I can rekindle the relationship. We dated for nine months, the last six months were long distance, but these nine months were a very intense and extremely bonding time. After only two months I had met and stayed with her parents in her childhood home, and after only one month we both said I love you. She was very sad to break up with me (cried the whole time) and said that I am very special to her and she loves me. She said she still wants to be friends, but doesn't know how to not be in a relationship with me. She said she would want to contact me every once in a while, but I said I'll need time, so we decided that I would be the one who contacts her when I'm ready.
I know because our bond was so strong that she still has feelings for me, at least for now. Do I wait to tell her what I've learned, or contact her sometime in the future? My emotions are still very raw so I will definitely wait some time, but maybe this relationship is just over? please help