AIO for being upset at my gf for going over her “guy friends” house then making out with him, then wanting to see him AGAIN??

Me (20m) with my gf (18f). First text is her trying to gaslight me into thinking she did nothing wrong. 2nd photo is the text exchange between her and this guy.. she claims she will tell him that they are just friends and cant kiss or do anything, but why is she leading him on then? This is my first love, and I’m really really annnoyed by this.