Reddit I need your help. Im trying to work through some shit with my ex, but she still keeps talking to other guys and is kinda secretive about it. It really bothers me, any advice?

We have been together for about 7 months now. We broke up a month ago cause I just feel like I couldnt trust her, but I really really care about her and I want it to work so thats why I went back and trying to work on it. One of the reasons why we broke up was cause she was talking to other guys when we were together and that just really bothers me cause it wasnt in a friend way it was kinda like a flirty way. I told her it hurt me and that I hate that. Lately she has been texting and talking to someone and everytime I ask her who she is talking to she wont tell me. She said before I had full rights to her phone, I never wanted to go through her phone cause Im not the type of person who wants to constantly spy on my girlfriend. When I tried to say what happened to my rights to her phone, she got all defensive and said oh so your going to pull that on me. So what should I do this really bothers me and it seems like nothing is changing. I wouldnt mind if she was texting friends but Im pretty sure these arent "just friends". She texts them right infront of me too she trys to be all secretive and hide her screen while she texts, its like she thinks im stupid. Is this fucked up or am I just trippin?