Sounds to me that your ex been wanting to break up with you for a minute and used the friend situation as an excuse. It isn’t normal to break up and block numbers over having an opinion about friends, especially if she has shared information to you about her friend.
This was more than likely some shyt that has accumulated over a period of time and instead of being a boss lady and charging you to the game in a mature manner, went on kiddy mode and broke up with you over some super petty bs.
Now OP, I know you still like ol girl and probably want to make up, but don’t you do it! Since she want to play that game, then you play the game better than her by moving the fukk on! I don’t care how bad you wanna talk to her, you put her immature ass on the benign neglect program starting now and don’t say a gd thing to her unless you absolutely have to(work related shyt).
Allow yourself to get over this lil girl and once you do that, hit the pavement and start campaigning for some new women. Best believe when your ex see you dating women, especially one that looks better than her, then she gonna want to talk to you again. Your situation isn’t normal, but it is quite common.