Expert: Don - 12/5/2007

Question
My boyfriend and I have been dating for 7 months. I have had suspicions of him cheating several times and anytime i bring it up he gets very angry and defensive and keeps saying "I never cheated on you" (emphasizing the never). Recently, he has had a co worker text messaging him at night saying things like "hope you're having a good night" and "see you tonight?". she even frequently calls him "jerk" like a pet name or something.  he hides his phone now, locks it, and makes sure to delete the calls and text messages every time i come over. he keeps reassuring me that it's just a friend and she is harmless. last night, she sent one saying "see you tonight?" and i asked him to text back "no, i am with my girlfriend" but he wouldn't. i don't even think she knows we are together and i have his facebook password and she is friends on it. he never checks it. how could i go about asking her what goes on between them without her knowing it isn't him and saying something to him at work? i just want to know if she knows he has a girlfriend, has done anything with her, or if he is planning on doing something with her. oh yeah, i have never met her, he won't introduce us. thanks.

Answer
You can long in and say, I sure had fun the other night and see if she will respond to about what happened.

Or you can pretend you want to date her, send her a note from you boyfriend asking her would she like to get together with him, if she says yes or something along the lines of we've already been together then you know he's sleeping with her.