I have a very close male friend who up until recently had a girlfriend. We are all in the same friend group so I do know her as well although i wouldn't say we are super close and she is way less involved in the group. Quite a while ago they opened their relationship, him and me started having something and leading a sort of friendship with benefits as was intended in the open relationship going slow almost like starting a relationship and that's how it developed as well. After a while the girlfriend got jealous and felt we were getting too close. They closed the relationship and him and me stopped having something, we were only allowed to see each other out of the house and obv not have anything sexually. However it became apparent that she felt increasingly uncomfortable because he still wanted to be close to me and so they tightened the rules. Now we weren't allowed to see each other at all besides in group settings and talk with each other one on one about anything privat or personal. This was hard for me and him, we were best friends way before and were each others emotional support in many ways but for a bit this was it. Then one evening he texted me asking me if I wanted to come over, he explained that his gf and him had talked and tonight was an exception. He didn't specify what they agreed on and because I had always be able to trust him i didn't ask to specify (learned a lesson there...). But he initiated something he shouldn't have. He told her after immediately, they talked and agreed to try and fix their relationship. The next couple of months were incredibly messy. Understandably now me and him weren't allowed to talk at all and she hated me although she did say it was primarily his fault. I can't really explain it but although he fucked me over as well I wasn't really mad at him, I couldn't be angry at him anyways. Everything sucked. As we are all in the same friend group we still saw each other quite a lot and that was really weird too, there was no way to ever really get over each other or what had happened. They broke up a couple weeks ago after his therapist had told him the relationship was just harmful for both of them at this point. They broke up mutually and still want to be good towards each other. Now here's my part. After they broke up him and me after months of "forcibly" being distant met up and talked, now we are seeing each other again. We are on weird terms, a mix of friendship and something more. His ex gf is obviously not happy and she wants us to still be distant. I feel conflicted. I guess I should be mad at him, I guess i should be supportive of her in a way even though she hates me. I probably am an asshole, he for sure is but I also unfortunately never really hated him and I still don't. He still feels like a best friend and I don't know if that makes me an asshole.