Men everywhere in this situation are wondering "how do I get my cheating girlfriend back?" Some people are shocked and amazed by the sheer volume of people willing and eager to work things out with someone who has already cheated on them.
I believe this is good news. While no one likes to hurt in this manner, more and more people are beginning to understand that there are a few worse things that can happen in a relationship.
The problem is she might believe that she's messed up so big the relationship cannot be saved. She may even believe that she is in love with the man she cheated on you with.
In other words, there may be some obstacles to overcome even though she is the one who did wrong to begin with. Don't forgive too quickly though. Take your time and make sure that you are really interested in working things out with her and that this isn't a knee-jerk reaction to the possibility of losing her.
So, how do you get her back and work out what's wrong with the relationship?
1) Understand that people in happy and healthy relationships don't generally cheat. There is something missing or incomplete in the relationship. There's no point in even attempting to work things out until you find out what that is and work out a way to bridge the gap or fix what is broken.
2) Make the necessary changes so that you can begin moving in the right direction. This is much easier if she's on board and working with you to build a stronger relationship but she does not have to be involved in order to do this step. The changes that you need to make you can do with or without her.
3) Brush up on romantic and sexual techniques. You don't have to go out and practice on a bunch of different women. In fact, that's a really bad idea right now. What you do want to do is read a few books that might help you see things from her perspective. This will help you give her what she needs. It's not all about technique or prowess but sometimes it is about a little something she needs that you don't offer. It doesn't help to study the other sex and find out what they want from men. It might be completely enlightening for you and life saving for your relationship.