This depends on two things. The first is what you did that requires forgiveness, and secondly, how much of a forgiving nature your girlfriend has. If you knew before you did this thing that she’d have a problem with it, then you have a third problem to think about!
There are some things that a girl will be willing to overlook — eventually. She won’t forget, and you’re likely to hear about it from time to time for the entire time your relationship lasts, but she will forgive you and let you near her again. This could be something like forgetting her birthday, forgetting an anniversary, not telling her that you weren’t meeting her as usual on Friday because it was a special night out with the guys, or other minimal damage transgression.
The best way around this situation is to try and make amends with a peace offering that’s proportionate to how badly you’ve messed up! Anything from flowers and chocolates, to a romantic dinner at an expensive restaurant (you pick up the tab!) may be required but you’ll probably get back into her arms with a warning not to do it again.
If you’ve really screwed up however, and want her back having done something on the magnitude of cheating on her — even if you didn’t sleep with the other girl, cheating is cheating in a girlfriend’s eyes — then you’ve got a much bigger problem. This one might not go away and so you’re going to have to work really hard to get her to forgive you.
Cheating isn’t just the fact that you made a pass at, kissed, and/or dated another girl. It’s the fact that you broke the trust your girlfriend had in you, and trust is a foundation stone for relationship. You’ve compromised that foundation, now if you want that relationship to stand; you’ve got to secure it again. It’s going to take time and patience, but no matter how much you hear her say “I don’t know if I can trust you” remember it was you that created the situation so don’t get mad at her for keep going on about it!
You have to prove to her that you are back and you won’t cheat again. Usually this means that you first have to get her speaking to you again! Once she’s communicating, even if she’s mad, at least you’ve got a chance of getting her back. You can’t fight silence! If she’s yelling at you, then at least she cares enough to show you how angry and hurt she is. You can deal with that. Explain. Apologize. Don’t get mad at her — she’s the victim! You’re in a mess you made yourself so don’t dig the hole deeper by telling her it won’t happen again and she should get over it! She’s not going to “get over it” any time soon!
If you’re sincere in your apology however, and sound sincere in how you talk to her about how you feel about your relationship and how much you want her back, and most importantly, how sorry you are about the mistake, in time she will forgive you.
Again, she’s not going to forget what you did, and the trust issue will be around for a long time, but if she can see how genuinely sorry you are, and that you really do care about her, then she may at least come back to you and give the relationship another try.
Jane Saeman runs a site called along with info on dating and relationship on her blog at at http://www.Hot-Firefighters.com/blog2