I just...need to vent. Ignore this if you want.

I'm in a long distance relationship, my boyfriend's biggest fear is me cheating on him and obviously I don't want to do that. But earlier today, I shared my plans to go on a platonic dinner date with a girl and then she was spending the night. My boyfriend had made a joke like "no man could be mad at his girl for an affair with another girl...just send pics" as this girl had expressed interest in me. Well, I didn't understand that it was a joke, but I still had no plans on sleeping with this girl. But at the end of the night, things started getting heated, though we never got farther than getting to our underwear before she began to have a panic attack and went home. I was honest and told my boyfriend that this had happened (again, I didn't understand that he had been joking earlier, plus I have no feelings towards this girl. So I had taken it very lightly) Obviously my boyfriend was very upset, I didn't mean to hurt him but I did. And I hate myself for it. I don't want to beg for forgiveness, I deserve every bit of anger, disappointment, sadness, etc that he has to throw at me. He didn't curse me out or insult me, he's the most amazing man and I fucked it up and I regret it so much. I have depression and anxiety and I don't have healthy coping methods all the time. I cut myself tonight. I threw up and I cried and punched myself and almost burned myself in the shower. But if I didn't do that kind of stuff, I'd probably have killed myself by now.