My girlfriend continues to text another guy that likes her from her work?

I have been with my girlfriend for almost 3 and a half years. We've been though soo much together and I'm in love you with her and i know she loves me. But recently I've been having a problem. She just recently got a job and she has this co worker that always talks to her, compliments her, and wants to be around her. This guy has also texts her constantly and they text back and forth late at night. He's even like "we should go see a movie together". to her, and he knows shes has a bf. This guy obviously likes her. She tells me shes not hiding anything and tells me alot of details about this guy and what she texts her and even shows me her phone, but the last two times i saw her in person her inbox happened 2 be deleted, and i feel lik shes makin excuses. She says she doesn't like him and wouldn't do anything to hurt me or throw our relationship away. I have told her that i am uncomfortable with him texting u soo much and soo late at night. She says she understands but she still texts him, and sometimes if i tell her can u jus end the conversation there or say ur going to sleep but she says ur like controlling me and bein overprotective and she thinks i dont trust her. I dont know what to do. if i tell her im uncomfortable again she'll say the same thing and think im controllin her and dont trust her. This is hurting me inside and i dont know how much longer i can take it. I know she loves me but things jus don't add up. I'm thinking about breaking up or at least taking a break and staying away and not see her for a while. Maybe she'll start to rethinking things and miss me and come back for me. Idk what to do anymore and idk if this is the right move.