Be honest, straight forward, empathetic and polite. Going into this you must know this will end up possibly heated, you will likely not be thanked but disliked but apologizing takes a big person to admit they did wrong. And if you believe your doing this to break them up for him to be yours chances are this will not happen as they both will be upset. Do what you need to do as it is not right he has been treating her in this manner as I am sure your not the only one. Learn from this mistake and don't repeat this in the future.
tell her that her boyfriend cheated on her. she needs to know.
how do you know if your boyfriend has cheated
you go and tell him you cheated on him and tell him how sorry you are and ask him to forgive you.
Yes, definitely do and if he really does love you, then he will say its okay. Otherwise you are out the door.
beat him up.
tell him you cheated on him
kiss them
Dude your a lesbian.
He will tell you.. men never lie.
You guys need to talk about this and consider your options. Goood Luck!
They may be jealous... Or hate you. Either way, tell him its not true.
Tell him honestly & as soon as possible. Don't omit information, either. You were reckless. Since you cheated, face the consequences.