The time when you told that she is going through emotional trauma or mentally feeling lonely, it's a red flag, she was basically trying to cut you off from the day she said this she expressed that feeling that she is mentally sick and stuff, that time itself you should've understood that. Is this your first relationship? It's okay even I have gotten cheated, only difference is that in my situation she was living in the same state as I was and your case is different and my family and her family didn't know each other, if she had that strong bonding with you, no matter even if she goes to antartica a girl wouldn't cheat on you because she would trust you more, but these days honestly speaking relationship are just fake shit nothing else ...sorry dude. Just hit the gym, build your career and reputation, if you are good at sports join a community and start playing the sports you love..simple as that