Is she having an affair?
I think my girlfriend is having an affair with this guy at work.
Ever since she started at this new job, its 'Matt this and matt that'.
He's all she flipping talks about and I can't stand it.
She is also texting him a lot saying its work and that I have nothing to worry about.
She also doesn't leave her phone alone for a second, whereas before, she would often leave it lying around.
My mates say that I am being taken for a fool as its obvious she is up to something.
I managed to look at one text and it seemed innocent enough, but I am not sure!
I think you need to discuss what's going on with her and how you feel. It's important not to be aggressive but have a calm and considered discussion, including giving her an out if she wants to go with the other guy. Obviously people are attracted to each other, especially in the work place, and this is the most common place where affairs start. A close friendship with someone of the opposite sex very often leads to a sexual relationship.