About one month ago I found out that my girlfriend of 2 years was cheating on me with her "guy friend" I want to know what I could have done in this situations and maybe in future to prevent what happened to me from repeating itself.

Disclamer: If I sound like an in-experienced Beta teenager it is because I am. I am posting here because I don't know what to do and I did not know what to do.

So around September when the school year started ( I am a highschool senior) she started talking to this one guy, I thought nothing of it whatever I have girl-friends and she had guy friends, I trust her and I wasn't that worried, besides she hadn't failed to tell many guys in the past that she had a boyfriend and wasn't interested. She even asked me if I was jealous that they would talk and I said no, why would I be. She even asked if she could "hug" him, yeah why the fuck not that, what type of person gets jealous when their SO hugs others? After a while I had suspected that he liked my girlfriend, so I checked my girlfriends phone and holy shit. In the beginning this guy would hit on her but she would reply with phrases such as "I'm not sure throwaway would like that" and " i have a boyfriend" but she didn't stop talking to him and she never told me. weeks later the conversations were more sexual in nature, the replies to his advances would change to something like "hahhahah I'm sure throwaway wouldn't mind" and " At this point I don't even care." The funny thing is throughout all the texts there was some maintenance of plausible deniability although in my mind they were defiantly heavy filtering and what she did was a betrayal of trust. Instead of shutting down his sexual advances she would enjoy the validation she got from him. After I found out I dumped her and she played the victim card.

In my mind everything was going very well before she met him. Or maybe I am just naive.

I do not blame him for what happened as she was the one in the relationship, and not even her entirely. Now TRP is generally against guard matting and I know that it is not a viable strategy to tell your girl that she can't do or talk to a certain person because it might just bring them closer. So my question is could I have done something earlier or was it too late? and if so what should I have done. I feel as though under the right situation any girl can cheat so is there an effective strategy I could have employed from preventing this from happening or how I can prevent any girl from cheating in the future if she feels attraction towards someone else?

I read this post, how effective would strategies like these be https://www.reddit.com/r/TheRedPill/comments/2g1rka/committed_relationships_boundaries_and_cheating/