Help!

I need help and guidance.

Let me tell you my last 2 month story.

My partner and I have been together for 5 years. The last 2 years haven't been smooth. He lost motivation and enjoyment in his work. I was weak and one night I emotionally cheated on him with a guy who was giving me more attention than him. I confessed right away I felt so guilty.

We decided to go into a poly relationship. Maybe this was what I needed. I thought this would make me happy. However what I realised was I only wanted other men because I felt my relationship was lacking in something. Recently I've seen a giant change in him. He has a new job he loves, he is motivated and excited by life.

I realised poly wasn't for me. And we decided to go back to monogamy after 2 months of trying poly (no sex was had by either of us to external partners).

However he nearly fell in love with another woman and now is asking to be with her. I told him I couldn't handle seeing him with another woman. It would break me.

We compromised and he is now friends with her. But she won't let go. I don't trust her.

How do I allow myself to be okay with them being friends?. It hurts me everytime they text.

How can I be this hypocritical and not trust him this much when I cheated on him?

I need advice on letting him have her as a friend. I don't want to be controlling and break them up.