Is OTHER wrong in the post ? POST : TL;DR at bottom.

&amp;#x200B;

I'm seeing my ex-wife after 8 months of separation following a very clean, very civil divorce. Things are better than ever and we question our decision to divorce every day. We had been seeing each other off and on throughout the entire separation, going back and forth between wanting to make it work and wanting to move on. At one point during our moving on stage, her and my best friend hooked up. This is the guy I entrusted her with while I was deployed, as she's a bit of a social hermit, and I knew she'd need someone to keep her company (I know, I know, the irony). To my knowledge, I believe the two of them never fooled around during my absence. We divorced about 6 months after I returned home, and 6 months later they slept together.

Now, I understand that this was her attempt to move on, and I'm not mad at her about that. I slept with other people during this stage as well. What I'm upset about is that my friend was okay with this. I hesitate to call it "bro code," as I feel that cheapens the concept, but I feel like there is a code of ethics amongst friends. An agreement to respect sensitive situations like this. He doesn't know that I know, and I haven't spoken to him since. I feel like 6 months is way too soon for a friend to get involved like that. I feel like he should have contacted me somehow, to let me know what was occurring, not for my permission, because they're grown adults and can do what they want, but to at least respect our friendship. To my understanding, he refuses to talk about it with her. When it was happening, she tried to talk to him about me and he wanted no part of that conversation, which leads me to believe he feels it was wrong as well.

&amp;#x200B;

I want to make amends with him, but I can't help but feel angry at him for sweeping this under the rug, so to speak. I'm waiting, hoping that he contacts me so we can air it out. I'm hesitant to contact him myself because if I do, I feel like I'd ambush him with my knowledge of their "meeting" and force him to talk to me about it, rather than give him the opportunity to do so himself.

&amp;#x200B;

AITA for feeling betrayed?

&amp;#x200B;

TL;DR: Divorced after two years, ex and I were seeing each other off and on. About 6 months after the divorce, a very close friend ended up sleeping with her. He doesn't know I know, she was honest, her and I are working it out, as we're together again and plan on remarrying. Don't want to call it "bro code" but I feel like a code of ethics has been crossed by my friend and I feel betrayed. AITA?