Crying and begging will only turn her colder. Have you read Divorce Remedy? If not, get it ASAP. In the meantime, read those links Cadet sent. It will help you a lot.
Your W has probably lost respect for you as a man, b/c that's what wayward wives do. Your job is to show inner strength. Stand firmly on your beliefs, morals & principles. Do not compromise your values just to get her back.
Don't pursue her. Your marriage doesn't stand a chance until she ends the A. All you need to know about it is if she's still in contact with OM. If any contact, then she's involved emotionally, at least.
What are your ages, and ages of your kids?
The more information, the better we can help.
I hope you'll stick with us and post a lot.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!