My Gf was texting her Ex

My Gf and i have been together for quite awhile now, we have never had any trust problems and havent really started fighting until now. The other day her ex texted her, asking how she was and saying he wanted to get back together, she obviously said no and told me right away. I was fine with it and was ok with how she dealt with it. The other day she told me she was going to youth group at church and said he would be there, i told her to just ignore him and she said he would. someone then texted me and told me that they were hanging out and talking for most of the time. she then told me that she would block him because she didnt want him to ever become a distraction for us. Yesterday we were together and she got a text from someone i didnt know, ( im very good with respecting her privacy and usually never ask cause i know she usually only texts her girl friends) she told me it was a guy from her grade and that i didnt know him, i carried on and didnt even mind, i then saw that he was saying that he was in his feelings for her and wish she would like him again,she didnt know i saw so i then confronted her and told her to show me the username of who it was ( it was on snapchat) she said no at first but then after i told her i would leave she did right away and it was her ex... she had changed the contact name so i wouldnt recognize it and told me that she was afraid i would be upset knowing that she was texting him. he always tries texting her and i have called him and her out about it and told her to not feed him any attention and that he was just getting in the way of things. She said the only thing he was talking about was how he said he was gonna threaten our relationship and try to ruin it if he couldnt have her. she said he constantly texted her and wouldnt stop bringing up the situation. i told her to not talk to him constantly but she still did whether it was to talk him out of thinking that she would ever date him again or not, which i know she doesnt like him at all, all she was doing after that was telling him she loved me and couldnt deal with him getting in the way anymore. I dont know what to do or how to deal with this. Whether to allow her to make things right or to move on, I love her so much and we hangout alot and she tells me how much she loves me and i was in pain that she wasnt honest with me for one of the first times in our relationship. Should I allow her to fix things with us and make it right or should i break up with her?