Very carefully.
Sorry, I have a girlfriend = Es tut mir Leid, ich habe eine Freundin
you should say that you are sorry for what you have done.
im sorry to say this but he already have a girlfriend and her name is RENA KOMINE
If it is your fault , you say sorry . JUST SAY SORRY! Even it it is not your FAULT . Send her flowers , anything . Cheer her up!
It is always good to say "I'm Sorry" to anyone that you have done wrong regardless of how you feel about the situation.
Say oops sorry always out than in I all ways say.
Tell your girlfriend that you love her and that you made a really bad mistake.
I believe she trying to breakup with you - sorry.
you say how sorry you are and apologize to him and his girlfriend
I say no and yes because I would have nothing to do w/ him and he could say sorry
That would be for you to decide - meaning if they say sorry and you believe them then that would be up to you if you are going to forgive them or not. It is hard to trust someone that has breached it and some that say sorry just to fix what they did wrong knowing it was wrong but only say sorry to get through it.
Talk it out with her, say you're sorry and hope that she will accept your apology.