Vent! pls read and give advice, i want to know where things went wrong and if it’s on me

So basically i got a girlfriend, my friend knew before I did. I began liking her, she liked me. She asked me out I said yes obvi. I told my best friend. She got mad and said stuff like i knew her first, me and here have been friends longer then you have been. I told her it doesn’t take long to start liking someone and defended myself. She said sorry and said she wasn’t having a good day already and this was “surprising”.

         Fast forward my girlfriend was jealous of me and my best friend. My girlfriend went through my texts and came forward apologizing saying i read your texts. I broke up with her saying trust was a big thing and she broke it.

        Fast forward more i forgive her and started to get my feelings back again for her. Obliviously my friend doesn’t have to forgive her. She didn’t, they stopped talking. I asked my ex out again she made me happy more then my friend did (long story). My best friend didn’t like that and got mad. She didn’t understand why i forgave her. What my girlfriend read wasn’t anything personal me and my friends are stupid. We talk about the stupidest sh!t. The person your in a relationship doesn’t have to like your friends. It’s kinda about respect. Neither of them where going anywhere so, just be there and don’t talk to each if thats what you want. My best friend said i cant do this right now and stopped talking to for a week. My other best-friend confronted the situation and said this is awkward when is everything going to be okay. I said idk im always ready to talk, im just waiting for my friend to be ready to talk about her feelings about me dating again. 😐 Give in mind my girlfriend made me so happy. I wasn’t on edge. I was comfortable, and i was myself. I was happy and it might have been my meds, but i wasn’t depressed.

        Fast forward me and my friend are talking again. I seem happy until homecoming were i cried cuz i told my girlfriend she should be with her friends, but seeing everyone else together made me sad that i was left alone. I slept over her house and went home the next morning, and that morning she broke up with me. My friend did not give any support during this because she didn’t know what to say and would laugh.