Yes. Otherwise she will find out herself, and then you will be even more guilty. Apologise immediately and tell her you know it was wrong.
No
What is the point.
I NOT
Follow your gut
yes you should. It would be a nice thing to do.
tell them its in the friend handbook
Just say that since your a couple you should be honest if you cheated or something then tell her that if you did you can tell me but never say or accuse them of it they will break up with you if they didn't and you accused them of cheating
Yes, before you act guilty and she suspects you
you go and tell him you cheated on him and tell him how sorry you are and ask him to forgive you.
how do you know if your boyfriend has cheated
You shouldn't have done anything with him knowing he has a girlfriend.
Yes! You should tell her, you should also tell him how that made you feel. Think about it, you'd want to be told!!!!