When do they stop, when is enough, enough?

[bus boy]

Do they ever stop? I have deep feelings or notions in my mind of ever getting back with my ex. I don't miss her, don't pine for her, never want anything to do with her again. She left a long time ago, we had a sexual relationship for the past 8+ years. My T told me I have to advocate for s9. He was always asking when are we going to be together, I would ask his mom she always said no, said no to s9's requests as well. My T said s9 doesn't know your fighting for him, he's reaching out to you, he is going stop some day. She said you have to let him know your fighting for him bc she's not. From February 2015- May 2015 we never had sex. She wasn't talking to me. Out of the blue I get a call, let's go out of town, we had sex. If this is going to continue I thought, she is going to have to give me proper access to s9. I told s9, we had an existing court order. That it was his weekend to spend with daddy, he was so excited, he said mommy, mommy I'm having a sleep over with daddy. She shut that down pretty fast, broke his heart. From that day on she was worse than ever. She had a BF in no time and he was pretty much living at her house. She never introduced him to s9 until a few months but after that he was living there full time. It was on s9's bday that she made the introduction and that's also the day I found out as well. S9 called me and said all excited, mommys friend is coming to my bday. She made sure there was extra hurt involved in my finding out.

So I'm out of the Plc, that's ok, I'm working hard to move on. Why is she getting worse? She had a BF, I don't pay any mind to them, I don't ask s9 anything about them, I really don't care. Even if I was the monster she imagined I was, it's time to move on, if I was thus beast why all the sex over the years? She's in a committed r/s over a year now so just let go, why drag me into the drama. It makes it very hard for me to grow. I feel I am growing but it gets slowed down.