The first thing that you have to remember if you want to get your wife back is that tricks, harassment, threats, and begging are not the way to do it. Even if it does work neither of you will be happy. Instead try the honest approach, be honest with yourself and honest with your wife. If you are able to reconcile using this approach you will have a much stronger relationship and have a much better chance of making it work this time around.
When I say you have to be honest with yourself, I mean you have to take a cold hard look at the person you are. How did you really treat your wife? Did you show her, and the marriage, the respect it truly needed and deserved? Did you spend as much time working on your marriage as you did working on your forehand or golf swing? Where were your priorities really at during your marriage?
More than likely, if you're honest, you'll have to admit that one or more of those questions hits a little too close to home, and that's good. It's only after you've carefully considered these points that you can start to address some behaviors on your part that may have contributed to the end of your marriage.
Now, I know some of you might be thinking "Well, yeah, I made mistakes, but so did she". Of course she did but if that is where your mind went, you are missing the point. The point is for you to face up to what you did wrong not ignoring your issues and focusing on the faults of your wife.
That is the single biggest problem most relationships have. It is so much easier to see your partners faults than it is to see yours. But if you spend all your time focusing on their faults, and they do the same thing, no one is changing anything. There is just a lot of finger pointing going on and that will never make your marriage work.
So, for now, just concentrate on what you can change: you, and your behavior. If you change yourself it will be up to your wife to make her own changes. If she's not willing to do that then there is nothing more you can do. In most cases though, when one spouse makes a real change and a real effort the other spouse will meet them halfway.
It might also be a good idea for you to invest in a self help book or find a therapist. Many men prefer the book method since it's easier then opening up to a stranger. Men have been conditioned by society to think that they have to hide what they're feeling but hiding isn't beneficial when you're trying to figure out what you did wrong in your marriage.
This seemingly easy step is one that most people ignore. Maybe it just seems too hard to face up to their flaws, maybe they just don't really care that much about their marriage. Whatever the reason is, if you aren't willing to take the time to do this step, the chances that you will get your wife back are slim. Take the time to improve you then no matter what happens you'll be a better person.