AIO Girlfriend adding guys on Snapchat after cheating

My girlfriend and I have been together for a little over a year and half. She cheated, lied and did things behind my back for the first several months of our relationship and after I found out it took her months to actually stop. We broke up and got back together a few times trying to work things out. She would continue messaging guys and say it was strictly platonic and there was never anything between them but every time that was a lie.

She said that she would just quit talking to guys so that it wouldn't be an issue. As far as I know she did for a month or 2. She agreed not to add any more guys on Snapchat. I had a feeling she was talking to someone and her reddit was logged in on my phone. I looked and saw that she sent a guy her Snapchat. She says she isn't doing anything wrong and she should be allowed to have male friends. She says as long as her intentions are good and they aren't saying anything inappropriate that she isn't doing anything wrong. She thinks I'm over reacting to her talking to strange men on reddit and Snapchat because according to her she has changed and is doing better. She added a guy to Snapchat without telling me, said she was going to eventually but i didnt give her a chance. She says since I chose to stay with her I need to trust her and that she won't repeat the same mistakes even though shes following the same patterns. Whether or not they said or did anything inappropriate, she broke our agreement. This isn't the first time either. At this point I feel stupid for staying with her.