(19m) I need an outside perspective

You know at times when you know you’re right in every way possible that being logical,emotional and technical but you are so overwhelmed by the other person’s stupidity/arrogance you start questioning yourself

So here’s what happened, currently dating my gf (19f) and before it we were friends for around a month and a week ish , at the time I kinda didn’t wanna date for reasons I’m not gonna get into but she really grew on me , at the time I was friends with this other girl (21f) that I had a suspicion she liked me but I never entertained it and again didn’t want to date Fyi the 19f and 21f actually know each other since I met both of them in a class I took but she was not my type (the 21f is really hardcore goth almost demonic, no hate to gothic person but it was too hardcore) so when I decided hey i think I’m up for dating so I started dating my (19f) gf and she told me that I get jealous really ez so I decided to cut ties with the 21f to make my partner happy and my gf stumbled on the 21f’s instagram account and saw reposts related to me and songs i listen too (fyi I mentioned that I was friends with her before dating my gf and that I blocked her out of respect) and she got completely upset and accused me of cheating saying that why is she posting stuff related to you and you and her must of hooked up and stuff and I can’t prove myself since I deleted chats and blocked her and she was yelling and crying that I’m cheater and she doesn’t believe anything i say and that the trust between us is gone even tho I keep swearing I didn’t do anything and that someone liking me doesn’t mean I am cheating

and she is making claims that I did XYZ and that you have to rebuild the trust that was lost between us , I because I genuinely love this girl said okay I’ll build the trust back up again but since then it’s been really hard to get replies and harder to hang out and she seems very distant and unhappy, I understand from her perspective and I know what it looks like but I ask you the person reading this

Is someone else liking you in your current relationship outside of your partner cheating , ofc not right? As well as how can I “earn” her trust back (besides being patient which I’m doing and will continue to do)

If you read all this thank you so much and hope you have a wonderful day and week