If you’re looking to save your marriage alone because you made the mistake of actually breaking up in the first place, then have you got your work cut out for you. Its gonna take a whole lot of humility because you will need to do a whole lot of apologizing. Sit her down and try to explain that you weren't thinking when you asked for a divorce, and that you realize how big of a mistake that was. You might even tell her that you were speaking out of anger, because maybe you were.
Now of course, the sooner you get around to admitting that you made a mistake, and that you want to save your marriage, the better. If your spouse has time to think it over and think about why divorce might be a good idea, then you now have to fight an even tougher battle. Just make sure that you let her know quickly how much of a mistake the idea of divorce was, and that you dont want to lose your marriage. This will be hard, and you will need to swallow your pride, but if your serious about saving your marriage, then you need to do it.
And if you have waited too long, and she is starting to think its a good idea, this is where save marriage alone gets hard. Dont give into any raw emotions though. It might seem easier to be bitter and point the finger at your wife, but try to remain calm and collected. If you getting into a yelling and screaming match, this will only makes things worse. Be quick to admit your own wrong doings and be willing to listen and make changes.
There is a program written by an expert marriage consultant which has helped thousands of couples recover their marriage. It is called Save My Marriage Today by Amy Waterman.