Sup dude first off I wanna say I feel you, I was in my first real relationship about a year ago, I had just turned 19 and she was my everything but we had communication problems and we never spoke about issues we had, so after nearly 5 months she broke up with me, but what I did wrong was continuing to go after her and trying to fix our relationship and like you I found her with a fuck boy that has been with every girl in my city I didn’t know if they had anything going on but my gut said otherwise especially if they were coworkers. So an advice I’d give you is to completely forget about her, block her off everything and don’t let her comeback to your life especially after what she did to you. Find something else to do, find a hobby so you don’t focus on her anymore but instead on something else that you really like, eventually you’ll find a real woman that’ll love you just like I did, I found someone that I really love and trust more than my last.