It's not completely true that an affair will end all relationships. Many relationships can be saved, and trust rebuilt over time with hard work. What does it take to get your ex back after an affair? The main topic that needs to be worked on will be to rebuild the trust that has been lost.
If you have had an affair, what was it that caused you to stray? Is there something at the heart of your relationship that is broken? Any broken relationship has the possibility of being healed. You just need to find the real reason that you did this and correct it for good. Some reasons for cheating are the sex is not as good as it had been or she is just not around much for you any more.
If your relationship was in good shape, the chance of you straying are plenty slim. Having trust in your partner is also very important, if your girl can not trust you the relationship will not be a comfortable one. She will not trust you when you go out with friends or you are working late, she will always be looking over your shoulder.
If she takes you back after having an affair consider yourself lucky. Now you must do the right things at all times. You need to take on more responsibilities to show you can be trusted and you must follow through. This building of trust is going to take a long time. As your partner may be holding anger toward you for quite a while.
It's going to take a lot of patience on your behalf because you may have to hear about this affair from your girl every so often. The best you can do is just listen and move on. On the other hand if the comments do not stop and her anger does not lesson, then maybe getting back together is not in the cards.