Not sure what to do or what to think?

I have been with my girlfriend for about a year now and over the weekend we were making dinner and her phone went off and I grabbed it to give it to her. I saw that it was a message from a guy, he sent her two dick pics and said I can't wait to have sex with you tomorrow. She claims that she befriended him at work because she is trying to make friends. But I am not sure what to do or think?
Not sure what to do or what to think?
Post Opinion