Should I confront him about his online flirting?

ok so my boyfriend and I have been dating for a little more than 6 months. he seemed like such an amazing guy, he didnt go out to partys anymore he quit smoking for me...he pretty much seemed like the ideal boyfriend. then came the day when I was getting a little suspicious of his behavior so I went home and made a fake account on AIM and I pretended to be a girl that lives near him and I began to flirt. at first he sort of blew the girl off but then today we had a fight over stupid things like him always changing the subject to his problems and he always sees my problems as little issues nothing compared to his problems. so after this fight I decided to go on as the girl to see what he would do and I asked him if he wanted to meet up and have a beer and maybe get to know each other better and he agreed with no hesitation. oh and by the way I was talking to him over the phone and I heard that he was typing on the computer (he types like a grandma) and he lied to me saying that hes just talking to one of him guy friends from work. so we hung up and I kept pretending to be the girl and he was so nice and he even used the pet name he calls me on this girl. I am so upset so heartbroken!! im going to give him one chance to confess that hes going to meet up with this girl and if he doesnt tell me and he goes to see 'her' I dont know what I should do. we have made promises to each other that we wont go out with the opposite sex w/o the other knowing so what should I do now?? should I confront him?? but if I do then it will come out that I didnt trust him and I tricked him. I NEED HELP!!

tell him you caught him show him the profile of the girl.