Dating

Am I wrong to be mad over my new gf texting another guy?

So I just started dating a girl from work. A lot of the guys there hit on her and are usually always texting her asking her to hang out. We're trying to keep our new relationship to ourselves. But last night she texted me out of nowhere at around 2 am telling me she couldn't sleep. I started to talk to her and then she told me that she had been texting a guy from work and that he even brought her some food at around 1:30am. This guy is an idiot and he's very pompous and she told me that he had tried to make out with her a few months ago at a party. She also admitted that they text each other late at night and talk for hours. I got really mad because we usually text each other throughout the day but she never texts me late at night until last night. I got really mad and she insists that he's a nice guy but I really don't like him. The last message I sent her was me telling her that I was going to bed and that I hoped she had fun chatting with her friend. I haven't talked to her since then because im still really mad at her. It's obvious he still likes her and I don't like the fact that she's texting him. Am I wrong to be mad? He hasn't sent me any messages since last night so what should my next step be? Should I wait for her to message me or should I just cave in and pretend im not angry? Please help me guys I could really use some advice.
Am I wrong to be mad over my new gf texting another guy?
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