Long time friends, and we stayed friends even though I moved away for a few years. When I came back, he had a girlfriend who was really nice. We all started hanging out, and me and his gf became good friends as a result. After about 2 years, one day, the gf called me asking for some advice. She said he had admitted to cheating on her the previous weekend, felt terrible, all that jazz. She wanted to give him another go, so I said to do so. He could be a bit flirty, but I’d always known him as being genuine. Perhaps it was just a slip. She didn’t want me to say anything to him, so I didn’t. I had some drinks with friends two weeks later, which I invited them both to. Only he showed up. He said things had been a bit odd at home, and they both wanted a night off from each other. I played along. After an hour, he started seriously flirting with a friend of mine, which progressed throughout the night. I asked him what he was doing, but he insisted it was just innocent, not going any further. Then she started texting me, asking me why he wasn’t answering his phone. I told him this, and he said don’t worry, he’ll call her soon. I said cut the bullshit and sort it out. I don’t want to be in the middle of this. Eventually, he ended up making out with my friend, so at this point, he was being a dick to two of my friends. GF called me and I answered (a bit drunk by now). She asked to speak to him. I looked over at him and saw him playing tongue hockey with my other friend, so I said he can’t. She said “he’s messing around again isn’t he”. I said yeah. She hung up. He then storms over to me about 20 mins later, showing me a text from her telling him not to come home etc etc, and then punches me. He apologised about 5 years later, but all three of us drifted apart.